From 310fd066e91f454b990372ffa30e803cc8120975 Mon Sep 17 00:00:00 2001 From: Florian Merz Date: Thu, 11 Feb 2021 12:56:40 +0100 Subject: unslug zh-cn: move --- .../global_objects/proxy/handler/apply/index.html | 117 ------------- .../proxy/handler/construct/index.html | 130 -------------- .../proxy/handler/defineproperty/index.html | 181 ------------------- .../proxy/handler/deleteproperty/index.html | 149 ---------------- .../global_objects/proxy/handler/get/index.html | 177 ------------------- .../handler/getownpropertydescriptor/index.html | 168 ------------------ .../proxy/handler/getprototypeof/index.html | 141 --------------- .../global_objects/proxy/handler/has/index.html | 176 ------------------- .../global_objects/proxy/handler/index.html | 77 -------- .../proxy/handler/isextensible/index.html | 123 ------------- .../proxy/handler/ownkeys/index.html | 193 --------------------- .../proxy/handler/preventextensions/index.html | 120 ------------- .../global_objects/proxy/handler/set/index.html | 125 ------------- .../proxy/handler/setprototypeof/index.html | 124 ------------- .../global_objects/proxy/proxy/apply/index.html | 117 +++++++++++++ .../proxy/proxy/construct/index.html | 130 ++++++++++++++ .../proxy/proxy/defineproperty/index.html | 181 +++++++++++++++++++ .../proxy/proxy/deleteproperty/index.html | 149 ++++++++++++++++ .../global_objects/proxy/proxy/get/index.html | 177 +++++++++++++++++++ .../proxy/getownpropertydescriptor/index.html | 168 ++++++++++++++++++ .../proxy/proxy/getprototypeof/index.html | 141 +++++++++++++++ .../global_objects/proxy/proxy/has/index.html | 176 +++++++++++++++++++ .../proxy/proxy/isextensible/index.html | 123 +++++++++++++ .../global_objects/proxy/proxy/ownkeys/index.html | 193 +++++++++++++++++++++ .../proxy/proxy/preventextensions/index.html | 120 +++++++++++++ .../global_objects/proxy/proxy/set/index.html | 125 +++++++++++++ .../proxy/proxy/setprototypeof/index.html | 124 +++++++++++++ 27 files changed, 1924 insertions(+), 2001 deletions(-) delete mode 100644 files/zh-cn/web/javascript/reference/global_objects/proxy/handler/apply/index.html delete mode 100644 files/zh-cn/web/javascript/reference/global_objects/proxy/handler/construct/index.html delete mode 100644 files/zh-cn/web/javascript/reference/global_objects/proxy/handler/defineproperty/index.html delete mode 100644 files/zh-cn/web/javascript/reference/global_objects/proxy/handler/deleteproperty/index.html delete mode 100644 files/zh-cn/web/javascript/reference/global_objects/proxy/handler/get/index.html delete mode 100644 files/zh-cn/web/javascript/reference/global_objects/proxy/handler/getownpropertydescriptor/index.html delete mode 100644 files/zh-cn/web/javascript/reference/global_objects/proxy/handler/getprototypeof/index.html delete mode 100644 files/zh-cn/web/javascript/reference/global_objects/proxy/handler/has/index.html delete mode 100644 files/zh-cn/web/javascript/reference/global_objects/proxy/handler/index.html delete mode 100644 files/zh-cn/web/javascript/reference/global_objects/proxy/handler/isextensible/index.html delete mode 100644 files/zh-cn/web/javascript/reference/global_objects/proxy/handler/ownkeys/index.html delete mode 100644 files/zh-cn/web/javascript/reference/global_objects/proxy/handler/preventextensions/index.html delete mode 100644 files/zh-cn/web/javascript/reference/global_objects/proxy/handler/set/index.html delete mode 100644 files/zh-cn/web/javascript/reference/global_objects/proxy/handler/setprototypeof/index.html create mode 100644 files/zh-cn/web/javascript/reference/global_objects/proxy/proxy/apply/index.html create mode 100644 files/zh-cn/web/javascript/reference/global_objects/proxy/proxy/construct/index.html create mode 100644 files/zh-cn/web/javascript/reference/global_objects/proxy/proxy/defineproperty/index.html create mode 100644 files/zh-cn/web/javascript/reference/global_objects/proxy/proxy/deleteproperty/index.html create mode 100644 files/zh-cn/web/javascript/reference/global_objects/proxy/proxy/get/index.html create mode 100644 files/zh-cn/web/javascript/reference/global_objects/proxy/proxy/getownpropertydescriptor/index.html create mode 100644 files/zh-cn/web/javascript/reference/global_objects/proxy/proxy/getprototypeof/index.html create mode 100644 files/zh-cn/web/javascript/reference/global_objects/proxy/proxy/has/index.html create mode 100644 files/zh-cn/web/javascript/reference/global_objects/proxy/proxy/isextensible/index.html create mode 100644 files/zh-cn/web/javascript/reference/global_objects/proxy/proxy/ownkeys/index.html create mode 100644 files/zh-cn/web/javascript/reference/global_objects/proxy/proxy/preventextensions/index.html create mode 100644 files/zh-cn/web/javascript/reference/global_objects/proxy/proxy/set/index.html create mode 100644 files/zh-cn/web/javascript/reference/global_objects/proxy/proxy/setprototypeof/index.html (limited to 'files/zh-cn/web/javascript/reference/global_objects/proxy') diff --git a/files/zh-cn/web/javascript/reference/global_objects/proxy/handler/apply/index.html b/files/zh-cn/web/javascript/reference/global_objects/proxy/handler/apply/index.html deleted file mode 100644 index 62b8b67f5f..0000000000 --- a/files/zh-cn/web/javascript/reference/global_objects/proxy/handler/apply/index.html +++ /dev/null @@ -1,117 +0,0 @@ ---- -title: handler.apply() -slug: Web/JavaScript/Reference/Global_Objects/Proxy/handler/apply -tags: - - ECMAScript6 - - JavaScript - - Method - - Proxy -translation_of: Web/JavaScript/Reference/Global_Objects/Proxy/Proxy/apply ---- -
{{JSRef}}
- -

handler.apply() 方法用于拦截函数的调用。

- -
{{EmbedInteractiveExample("pages/js/proxyhandler-apply.html", "taller")}}
- - - -

语法

- -
var p = new Proxy(target, {
-  apply: function(target, thisArg, argumentsList) {
-  }
-});
-
- -

参数

- -

以下是传递给apply方法的参数，this上下文绑定在handler对象上.

- -
-
target
-
目标对象（函数）。
-
thisArg
-
被调用时的上下文对象。
-
argumentsList
-
被调用时的参数数组。
-
- -

返回值

- -

apply方法可以返回任何值。

- -

描述

- -

handler.apply 方法用于拦截函数的调用。

- -

拦截

- -

该方法会拦截目标对象的以下操作:

- - - -

约束

- -

如果违反了以下约束，代理将抛出一个TypeError：

- -

target必须是可被调用的。也就是说，它必须是一个函数对象。

- -

示例

- -

以下代码演示如何捕获函数的调用。

- -
var p = new Proxy(function() {}, {
-  apply: function(target, thisArg, argumentsList) {
-    console.log('called: ' + argumentsList.join(', '));
-    return argumentsList[0] + argumentsList[1] + argumentsList[2];
-  }
-});
-
-console.log(p(1, 2, 3)); // "called: 1, 2, 3"
-                         // 6
-
- -

规范

- - - - - - - - - - - - - - - - - - - -
SpecificationStatusComment
{{SpecName('ES2015', '#sec-proxy-object-internal-methods-and-internal-slots-call-thisargument-argumentslist', '[[Call]]')}}{{Spec2('ES2015')}}Initial definition.
{{SpecName('ESDraft', '#sec-proxy-object-internal-methods-and-internal-slots-call-thisargument-argumentslist', '[[Call]]')}}{{Spec2('ESDraft')}} 
- -

浏览器兼容性

- -
- - -

{{Compat("javascript.builtins.Proxy.handler.apply")}}

-
- -

另见

- - diff --git a/files/zh-cn/web/javascript/reference/global_objects/proxy/handler/construct/index.html b/files/zh-cn/web/javascript/reference/global_objects/proxy/handler/construct/index.html deleted file mode 100644 index 209e9752e3..0000000000 --- a/files/zh-cn/web/javascript/reference/global_objects/proxy/handler/construct/index.html +++ /dev/null @@ -1,130 +0,0 @@ ---- -title: handler.construct() -slug: Web/JavaScript/Reference/Global_Objects/Proxy/handler/construct -translation_of: Web/JavaScript/Reference/Global_Objects/Proxy/Proxy/construct ---- -
{{JSRef}}
- -

handler.construct() 方法用于拦截{{jsxref("Operators/new", "new")}} 操作符. 为了使new操作符在生成的Proxy对象上生效，用于初始化代理的目标对象自身必须具有[[Construct]]内部方法（即 new target 必须是有效的）。

- -

{{EmbedInteractiveExample("pages/js/proxyhandler-construct.html", "taller")}}

- -

语法

- -
var p = new Proxy(target, {
-  construct: function(target, argumentsList, newTarget) {
-  }
-});
-
- -

参数

- -

下面的参数将会传递给construct方法，this绑定在handler上。

- -
-
target
-
目标对象。
-
argumentsList
-
constructor的参数列表。
-
newTarget
-
最初被调用的构造函数，就上面的例子而言是p。
-
- -

返回值

- -

construct 方法必须返回一个对象。

- -

描述

- -

handler.construct() 方法用于拦截 {{jsxref("Operators/new", "new")}}操作符。

- -

拦截

- -

该拦截器可以拦截以下操作:

- - - -

约束

- -

如果违反以下约定，代理将会抛出错误 {{jsxref("TypeError")}}:

- - - -

示例

- -

下面代码演示如何拦截 {{jsxref("Operators/new", "new")}} 操作。

- -
var p = new Proxy(function() {}, {
-  construct: function(target, argumentsList, newTarget) {
-    console.log('called: ' + argumentsList.join(', '));
-    return { value: argumentsList[0] * 10 };
-  }
-});
-
-console.log(new p(1).value); // "called: 1"
-                             // 10
-
- -

下面的代码违反了约定.

- -
var p = new Proxy(function() {}, {
-  construct: function(target, argumentsList, newTarget) {
-    return 1;
-  }
-});
-
-new p(); // TypeError is thrown
-
- -

下面的代码未能正确的初始化Proxy。Proxy初始化时，传给它的target 必须具有一个有效的constructor供new操作符调用。

- -
var p = new Proxy({}, {
-  construct: function(target, argumentsList, newTarget) {
-    return {};
-  }
-});
-
-new p(); // TypeError is thrown, "p" is not a constructor
-
- -

规范

- - - - - - - - - - - - - - - - - - - -
SpecificationStatusComment
{{SpecName('ES2015', '#sec-proxy-object-internal-methods-and-internal-slots-construct-argumentslist-newtarget', '[[Construct]]')}}{{Spec2('ES2015')}}Initial definition.
{{SpecName('ESDraft', '#sec-proxy-object-internal-methods-and-internal-slots-construct-argumentslist-newtarget', '[[Construct]]')}}{{Spec2('ESDraft')}} 
- -

浏览器兼容性

- -
{{Compat("javascript.builtins.Proxy.handler.construct")}}
- -
 
- -

相关主题

- - diff --git a/files/zh-cn/web/javascript/reference/global_objects/proxy/handler/defineproperty/index.html b/files/zh-cn/web/javascript/reference/global_objects/proxy/handler/defineproperty/index.html deleted file mode 100644 index 9912e043a0..0000000000 --- a/files/zh-cn/web/javascript/reference/global_objects/proxy/handler/defineproperty/index.html +++ /dev/null @@ -1,181 +0,0 @@ ---- -title: handler.defineProperty() -slug: Web/JavaScript/Reference/Global_Objects/Proxy/handler/defineProperty -translation_of: Web/JavaScript/Reference/Global_Objects/Proxy/Proxy/defineProperty ---- -
{{JSRef}}
- -

handler.defineProperty() 用于拦截对对象的 {{jsxref("Object.defineProperty()")}} 操作。

- -

语法

- -
var p = new Proxy(target, {
-  defineProperty: function(target, property, descriptor) {
-  }
-});
-
- -

参数

- -

下列参数将会被传递给 defineProperty 方法。 this 绑定在 handler 对象上。

- -
-
target
-
目标对象。
-
property
-
待检索其描述的属性名。
-
descriptor
-
待定义或修改的属性的描述符。
-
- -

返回值

- -

defineProperty 方法必须以一个 {{jsxref("Boolean")}} 返回，表示定义该属性的操作成功与否。

- -

描述

- -

handler.defineProperty() 用于拦截对对象的 {{jsxref("Object.defineProperty()")}} 操作。

- -

拦截

- -

该方法会拦截目标对象的以下操作 :

- - - -

不变量

- -

如果违背了以下的不变量，proxy会抛出 {{jsxref("TypeError")}}:

- - - -

示例

- -

以下代码演示如何拦截对目标对象的 {{jsxref("Object.defineProperty()")}} 操作。

- -
var p = new Proxy({}, {
-  defineProperty: function(target, prop, descriptor) {
-    console.log('called: ' + prop);
-    return true;
-  }
-});
-
-var desc = { configurable: true, enumerable: true, value: 10 };
-Object.defineProperty(p, 'a', desc); // "called: a"
-
- -

当调用 {{jsxref("Object.defineProperty()")}} 或者 {{jsxref("Reflect.defineProperty()")}}，传递给 defineProperty 的 descriptor   有一个限制 - 只有以下属性才有用，非标准的属性将会被无视 :

- - - -
var p = new Proxy({}, {
-  defineProperty(target, prop, descriptor) {
-    console.log(descriptor);
-    return Reflect.defineProperty(target, prop, descriptor);
-  }
-});
-
-Object.defineProperty(p, 'name', {
-  value: 'proxy',
-  type: 'custom'
-});  // { value: 'proxy' }
-
- -

规范

- - - - - - - - - - - - - - - - - - - -
SpecificationStatusComment
{{SpecName('ES2015', '#sec-proxy-object-internal-methods-and-internal-slots-defineownproperty-p-desc', '[[DefineOwnProperty]]')}}{{Spec2('ES2015')}}Initial definition.
{{SpecName('ESDraft', '#sec-proxy-object-internal-methods-and-internal-slots-defineownproperty-p-desc', '[[DefineOwnProperty]]')}}{{Spec2('ESDraft')}}
- -

浏览器兼容性

- -
{{CompatibilityTable}}
- -
- - - - - - - - - - - - - - - - - - - -
FeatureChromeFirefox (Gecko)Internet ExplorerOperaSafari
Basic support{{CompatUnknown}}{{CompatGeckoDesktop("18")}}{{CompatUnknown}}{{CompatUnknown}}{{CompatUnknown}}
-
- -
- - - - - - - - - - - - - - - - - - - - - -
FeatureAndroidChrome for AndroidFirefox Mobile (Gecko)IE MobileOpera MobileSafari Mobile
Basic support{{CompatUnknown}}{{CompatUnknown}}{{CompatGeckoMobile("18")}}{{CompatUnknown}}{{CompatUnknown}}{{CompatUnknown}}
-
- -

另见

- - diff --git a/files/zh-cn/web/javascript/reference/global_objects/proxy/handler/deleteproperty/index.html b/files/zh-cn/web/javascript/reference/global_objects/proxy/handler/deleteproperty/index.html deleted file mode 100644 index 6cb4255755..0000000000 --- a/files/zh-cn/web/javascript/reference/global_objects/proxy/handler/deleteproperty/index.html +++ /dev/null @@ -1,149 +0,0 @@ ---- -title: handler.deleteProperty() -slug: Web/JavaScript/Reference/Global_Objects/Proxy/handler/deleteProperty -translation_of: Web/JavaScript/Reference/Global_Objects/Proxy/Proxy/deleteProperty ---- -
{{JSRef}}
- -

handler.deleteProperty() 方法用于拦截对对象属性的 {{jsxref("Operators/delete", "delete")}} 操作。

- -

语法

- -
var p = new Proxy(target, {
-  deleteProperty: function(target, property) {
-  }
-});
-
- -

参数

- -

deleteProperty 方法将会接受以下参数。 this 被绑定在 handler上。

- -
-
target
-
目标对象。
-
property
-
待删除的属性名。
-
- -

返回值

- -

deleteProperty 必须返回一个 {{jsxref("Boolean")}} 类型的值，表示了该属性是否被成功删除。

- -

描述

- -

handler.deleteProperty() 方法可以拦截 {{jsxref("Operators/delete", "delete")}} 操作。

- -

拦截

- -

该方法会拦截以下操作:

- - - -

不变量

- -

如果违背了以下不变量，proxy 将会抛出一个 {{jsxref("TypeError")}}:

- - - -

示例

- -

以下代码演示了对 {{jsxref("Operators/delete", "delete")}} 操作的拦截。

- -
var p = new Proxy({}, {
-  deleteProperty: function(target, prop) {
-    console.log('called: ' + prop);
-    return true;
-  }
-});
-
-delete p.a; // "called: a"
-
- -

规范

- - - - - - - - - - - - - - - - - - - -
SpecificationStatusComment
{{SpecName('ES2015', '#sec-proxy-object-internal-methods-and-internal-slots-delete-p', '[[Delete]]')}}{{Spec2('ES2015')}}Initial definition.
{{SpecName('ESDraft', '#sec-proxy-object-internal-methods-and-internal-slots-delete-p', '[[Delete]]')}}{{Spec2('ESDraft')}} 
- -

浏览器兼容性

- -
{{CompatibilityTable}}
- -
- - - - - - - - - - - - - - - - - - - -
FeatureChromeFirefox (Gecko)Internet ExplorerOperaSafari
Basic support{{CompatUnknown}}{{CompatGeckoDesktop("18")}}{{CompatUnknown}}{{CompatUnknown}}{{CompatUnknown}}
-
- -
- - - - - - - - - - - - - - - - - - - - - -
FeatureAndroidChrome for AndroidFirefox Mobile (Gecko)IE MobileOpera MobileSafari Mobile
Basic support{{CompatUnknown}}{{CompatUnknown}}{{CompatGeckoMobile("18")}}{{CompatUnknown}}{{CompatUnknown}}{{CompatUnknown}}
-
- -

另见

- - diff --git a/files/zh-cn/web/javascript/reference/global_objects/proxy/handler/get/index.html b/files/zh-cn/web/javascript/reference/global_objects/proxy/handler/get/index.html deleted file mode 100644 index 14a350436a..0000000000 --- a/files/zh-cn/web/javascript/reference/global_objects/proxy/handler/get/index.html +++ /dev/null @@ -1,177 +0,0 @@ ---- -title: handler.get() -slug: Web/JavaScript/Reference/Global_Objects/Proxy/handler/get -tags: - - ECMAScript6 - - JavaScript - - Method - - Proxy -translation_of: Web/JavaScript/Reference/Global_Objects/Proxy/Proxy/get ---- -
{{JSRef}}
- -

handler.get() 方法用于拦截对象的读取属性操作。

- -

语法

- -
var p = new Proxy(target, {
-  get: function(target, property, receiver) {
-  }
-});
-
- -

参数

- -

以下是传递给get方法的参数，this上下文绑定在handler对象上.

- -
-
target
-
目标对象。
-
property
-
被获取的属性名。
-
receiver
-
Proxy或者继承Proxy的对象
-
- -

返回值

- -

get方法可以返回任何值。

- -

描述

- -

handler.get 方法用于拦截对象的读取属性操作。

- -

拦截

- -

该方法会拦截目标对象的以下操作:

- - - -

约束

- -

如果违背了以下的约束，proxy会抛出 {{jsxref("TypeError")}}:

- - - -

示例

- -

以下代码演示如何拦截属性值的读取操作。

- -
var p = new Proxy({}, {
-  get: function(target, prop, receiver) {
-    console.log("called: " + prop);
-    return 10;
-  }
-});
-
-console.log(p.a); // "called: a"
-                  // 10
-
- -

以下代码演示违反约束的情况。

- -
var obj = {};
-Object.defineProperty(obj, "a", {
-  configurable: false,
-  enumerable: false,
-  value: 10,
-  writable: false
-});
-
-var p = new Proxy(obj, {
-  get: function(target, prop) {
-    return 20;
-  }
-});
-
-p.a; //会抛出TypeError
-
- -

规范

- - - - - - - - - - - - - - - - - - - -
SpecificationStatusComment
{{SpecName('ES2015', '#sec-proxy-object-internal-methods-and-internal-slots-get-p-receiver', '[[Get]]')}}{{Spec2('ES2015')}}Initial definition.
{{SpecName('ESDraft', '#sec-proxy-object-internal-methods-and-internal-slots-get-p-receiver', '[[Get]]')}}{{Spec2('ESDraft')}} 
- -

浏览器兼容性

- -
{{CompatibilityTable}}
- -
- - - - - - - - - - - - - - - - - - - -
FeatureChromeFirefox (Gecko)Internet ExplorerOperaSafari
Basic support{{CompatUnknown}}{{CompatGeckoDesktop("18")}}{{CompatUnknown}}{{CompatUnknown}}{{CompatUnknown}}
-
- -
- - - - - - - - - - - - - - - - - - - - - -
FeatureAndroidChrome for AndroidFirefox Mobile (Gecko)IE MobileOpera MobileSafari Mobile
Basic support{{CompatUnknown}}{{CompatUnknown}}{{CompatGeckoMobile("18")}}{{CompatUnknown}}{{CompatUnknown}}{{CompatUnknown}}
-
- -

另见

- - diff --git a/files/zh-cn/web/javascript/reference/global_objects/proxy/handler/getownpropertydescriptor/index.html b/files/zh-cn/web/javascript/reference/global_objects/proxy/handler/getownpropertydescriptor/index.html deleted file mode 100644 index 470b2c6ad9..0000000000 --- a/files/zh-cn/web/javascript/reference/global_objects/proxy/handler/getownpropertydescriptor/index.html +++ /dev/null @@ -1,168 +0,0 @@ ---- -title: handler.getOwnPropertyDescriptor() -slug: Web/JavaScript/Reference/Global_Objects/Proxy/handler/getOwnPropertyDescriptor -translation_of: Web/JavaScript/Reference/Global_Objects/Proxy/Proxy/getOwnPropertyDescriptor ---- -
{{JSRef}}
- -

handler.getOwnPropertyDescriptor() 方法是 {{jsxref("Object.getOwnPropertyDescriptor()")}}  的钩子。

- -

语法

- -
var p = new Proxy(target, {
-  getOwnPropertyDescriptor: function(target, prop) {
-  }
-});
-
- -

参数

- -

下列参数会被传入 getOwnPropertyDescriptor 方法中。这是绑定到handler上。 

- -
-
target
-
目标对象。
-
prop
-
返回属性名称的描述。
-
- -

返回值

- -

getOwnPropertyDescriptor 方法必须返回一个 object 或 undefined。

- -

描述

- -

handler.getOwnPropertyDescriptor() 方法是 {{jsxref("Object.getOwnPropertyDescriptor()")}} 的陷阱。

- -

拦截

- -

这个陷阱可以拦截这些操作：

- - - -

不变量

- -

如果下列不变量被违反，代理将抛出一个 {{jsxref("TypeError")}}：

- - - -

示例

- -

以下是 {{jsxref("Object.getOwnPropertyDescriptor()")}} 的代码陷阱：

- -
var p = new Proxy({ a: 20}, {
-  getOwnPropertyDescriptor: function(target, prop) {
-    console.log('called: ' + prop);
-    return { configurable: true, enumerable: true, value: 10 };
-  }
-});
-
-console.log(Object.getOwnPropertyDescriptor(p, 'a').value); // "called: a"
-                                                            // 10
-
- -

以下代码则违反了不变量。

- -
var obj = { a: 10 };
-Object.preventExtensions(obj);
-var p = new Proxy(obj, {
-  getOwnPropertyDescriptor: function(target, prop) {
-    return undefined;
-  }
-});
-
-Object.getOwnPropertyDescriptor(p, 'a'); // TypeError is thrown
-
- -

规范

- - - - - - - - - - - - - - - - - - - -
SpecificationStatusComment
{{SpecName('ES2015', '#sec-proxy-object-internal-methods-and-internal-slots-getownproperty-p', '[[GetOwnProperty]]')}}{{Spec2('ES2015')}}Initial definition.
{{SpecName('ESDraft', '#sec-proxy-object-internal-methods-and-internal-slots-getownproperty-p', '[[GetOwnProperty]]')}}{{Spec2('ESDraft')}}
- -

浏览器兼容性

- -
{{CompatibilityTable}}
- -
- - - - - - - - - - - - - - - - - - - -
FeatureChromeFirefox (Gecko)Internet ExplorerOperaSafari
Basic support{{CompatUnknown}}{{CompatGeckoDesktop("18")}}{{CompatUnknown}}{{CompatUnknown}}{{CompatUnknown}}
-
- -
- - - - - - - - - - - - - - - - - - - - - -
FeatureAndroidChrome for AndroidFirefox Mobile (Gecko)IE MobileOpera MobileSafari Mobile
Basic support{{CompatUnknown}}{{CompatUnknown}}{{CompatGeckoMobile("18")}}{{CompatUnknown}}{{CompatUnknown}}{{CompatUnknown}}
-
- -

相关链接

- - diff --git a/files/zh-cn/web/javascript/reference/global_objects/proxy/handler/getprototypeof/index.html b/files/zh-cn/web/javascript/reference/global_objects/proxy/handler/getprototypeof/index.html deleted file mode 100644 index 215d2d9646..0000000000 --- a/files/zh-cn/web/javascript/reference/global_objects/proxy/handler/getprototypeof/index.html +++ /dev/null @@ -1,141 +0,0 @@ ---- -title: handler.getPrototypeOf() -slug: Web/JavaScript/Reference/Global_Objects/Proxy/handler/getPrototypeOf -tags: - - ECMAScript 2015 - - JavaScript - - Method - - Proxy - - 方法 -translation_of: Web/JavaScript/Reference/Global_Objects/Proxy/Proxy/getPrototypeOf ---- -
{{JSRef("Global_Objects", "Proxy")}}
- -

handler.getPrototypeOf() 是一个代理（Proxy）方法，当读取代理对象的原型时，该方法就会被调用。

- -
{{EmbedInteractiveExample("pages/js/proxyhandler-getprototypeof.html", "taller")}}
- - - -

语法

- -
const p = new Proxy(obj, {
-  getPrototypeOf(target) {
-  ...
-  }
-});
-
- -

参数

- -

当 getPrototypeOf 方法被调用时，this 指向的是它所属的处理器对象。

- -
-
target
-
被代理的目标对象。
-
- -

返回值

- -

getPrototypeOf 方法的返回值必须是一个对象或者 null。

- -

描述

- -

在 JavaScript 中，下面这五种操作（方法/属性/运算符）可以触发 JS 引擎读取一个对象的原型，也就是可以触发 getPrototypeOf() 代理方法的运行：

- - - -

如果遇到了下面两种情况，JS 引擎会抛出 {{jsxref("TypeError")}} 异常：

- - - -

示例

- -

基本用法

- -
var obj = {};
-var proto = {};
-var handler = {
-    getPrototypeOf(target) {
-        console.log(target === obj);   // true
-        console.log(this === handler); // true
-        return proto;
-    }
-};
-
-var p = new Proxy(obj, handler);
-console.log(Object.getPrototypeOf(p) === proto);    // true
-
- -

5 种触发 getPrototypeOf 代理方法的方式

- -
var obj = {};
-var p = new Proxy(obj, {
-    getPrototypeOf(target) {
-        return Array.prototype;
-    }
-});
-console.log(
-    Object.getPrototypeOf(p) === Array.prototype,  // true
-    Reflect.getPrototypeOf(p) === Array.prototype, // true
-    p.__proto__ === Array.prototype,               // true
-    Array.prototype.isPrototypeOf(p),              // true
-    p instanceof Array                             // true
-);
-
- -

两种情况下的异常

- -
var obj = {};
-var p = new Proxy(obj, {
-    getPrototypeOf(target) {
-        return "foo";
-    }
-});
-Object.getPrototypeOf(p); // TypeError: "foo" is not an object or null
-
-var obj = Object.preventExtensions({});
-var p = new Proxy(obj, {
-    getPrototypeOf(target) {
-        return {};
-    }
-});
-Object.getPrototypeOf(p); // TypeError: expected same prototype value
-
- -

规范

- - - - - - - - - - -
规范
{{SpecName('ESDraft', '#sec-proxy-object-internal-methods-and-internal-slots-getprototypeof', '[[GetPrototypeOf]]')}}
- -

浏览器兼容性

- - - -

{{Compat("javascript.builtins.Proxy.handler.getPrototypeOf")}}

- -

参见

- - diff --git a/files/zh-cn/web/javascript/reference/global_objects/proxy/handler/has/index.html b/files/zh-cn/web/javascript/reference/global_objects/proxy/handler/has/index.html deleted file mode 100644 index fead0846ff..0000000000 --- a/files/zh-cn/web/javascript/reference/global_objects/proxy/handler/has/index.html +++ /dev/null @@ -1,176 +0,0 @@ ---- -title: handler.has() -slug: Web/JavaScript/Reference/Global_Objects/Proxy/handler/has -translation_of: Web/JavaScript/Reference/Global_Objects/Proxy/Proxy/has ---- -
{{JSRef}}
- -

 handler.has() 方法是针对 {{jsxref("Operators/in", "in")}} 操作符的代理方法。

- - - - - -

{{EmbedInteractiveExample("pages/js/proxyhandler-has.html", "taller")}}

- - - - - -

语法

- -
var p = new Proxy(target, {
-  has: function(target, prop) {
-  }
-});
-
- -

参数

- -

下面是传递给 has 方法的参数. this is bound to the handler.

- -
-
target
-
目标对象.
-
prop
-
需要检查是否存在的属性.
-
- -

返回值

- -

has 方法返回一个 boolean 属性的值.

- -

描述

- -

handler.has 方法可以看作是针对 {{jsxref("Operators/in", "in")}} 操作的钩子.

- -

拦截

- -

这个钩子可以拦截下面这些操作:

- - - -

约束

- -

如果违反了下面这些规则,  proxy 将会抛出 {{jsxref("TypeError")}}:

- - - -

示例

- -

下面的代码拦截了 {{jsxref("Operators/in", "in")}} 操作符.

- -
var p = new Proxy({}, {
-  has: function(target, prop) {
-    console.log('called: ' + prop);
-    return true;
-  }
-});
-
-console.log('a' in p); // "called: a"
-                       // true
-
- -

下面的代码违反了约束.

- -
var obj = { a: 10 };
-Object.preventExtensions(obj);
-var p = new Proxy(obj, {
-  has: function(target, prop) {
-    return false;
-  }
-});
-
-'a' in p; // TypeError is thrown
-
- -

规范

- - - - - - - - - - - - - - - - - - - -
SpecificationStatusComment
{{SpecName('ES2015', '#sec-proxy-object-internal-methods-and-internal-slots-hasproperty-p', '[[HasProperty]]')}}{{Spec2('ES2015')}}Initial definition.
{{SpecName('ESDraft', '#sec-proxy-object-internal-methods-and-internal-slots-hasproperty-p', '[[HasProperty]]')}}{{Spec2('ESDraft')}}
- -

浏览器支持

- -
{{CompatibilityTable}}
- -
- - - - - - - - - - - - - - - - - - - -
FeatureChromeFirefox (Gecko)Internet ExplorerOperaSafari
Basic support{{CompatUnknown}}{{CompatGeckoDesktop("18")}}{{CompatUnknown}}{{CompatUnknown}}{{CompatUnknown}}
-
- -
- - - - - - - - - - - - - - - - - - - - - -
FeatureAndroidChrome for AndroidFirefox Mobile (Gecko)IE MobileOpera MobileSafari Mobile
Basic support{{CompatUnknown}}{{CompatUnknown}}{{CompatGeckoMobile("18")}}{{CompatUnknown}}{{CompatUnknown}}{{CompatUnknown}}
-
- -

其他

- - diff --git a/files/zh-cn/web/javascript/reference/global_objects/proxy/handler/index.html b/files/zh-cn/web/javascript/reference/global_objects/proxy/handler/index.html deleted file mode 100644 index 26d1ad3517..0000000000 --- a/files/zh-cn/web/javascript/reference/global_objects/proxy/handler/index.html +++ /dev/null @@ -1,77 +0,0 @@ ---- -title: Proxy handler -slug: Web/JavaScript/Reference/Global_Objects/Proxy/handler -tags: - - ECMAScript 2015 - - JavaScript - - Proxy -translation_of: Web/JavaScript/Reference/Global_Objects/Proxy/Proxy -translation_of_original: Web/JavaScript/Reference/Global_Objects/Proxy/handler ---- -
{{JSRef}}
- -
Proxy 的 handler 对象是一个占位符对象，它包含了用于 {{jsxref("Proxy")}} 的陷阱（Trap）函数。
- -
此处可以理解为由Proxy所暴露出的钩子函数，handler作为挂载钩子函数的对象存在，不同的操作会触发不同的钩子函数
- -
，handler提供了覆写钩子函数的方法。
- -

方法

- -

所有的陷阱是可选的。如果某个陷阱没有定义，那么就会保留默认行为。

- -
-
{{jsxref("Global_Objects/Proxy/handler/getPrototypeOf", "handler.getPrototypeOf()")}}
-
在读取代理对象的原型时触发该操作，比如在执行 {{jsxref("Object.getPrototypeOf")}}(proxy) 时。
-
{{jsxref("Global_Objects/Proxy/handler/setPrototypeOf", "handler.setPrototypeOf()")}}
-
在设置代理对象的原型时触发该操作，比如在执行 {{jsxref("Object.setPrototypeOf")}}(proxy, null) 时。
-
{{jsxref("Global_Objects/Proxy/handler/isExtensible", "handler.isExtensible()")}}
-
在判断一个代理对象是否是可扩展时触发该操作，比如在执行 {{jsxref("Object.isExtensible")}}(proxy) 时。
-
{{jsxref("Global_Objects/Proxy/handler/preventExtensions", "handler.preventExtensions()")}}
-
在让一个代理对象不可扩展时触发该操作，比如在执行 {{jsxref("Object.preventExtensions")}}(proxy) 时。
-
{{jsxref("Global_Objects/Proxy/handler/getOwnPropertyDescriptor", "handler.getOwnPropertyDescriptor()")}}
-
在获取代理对象某个属性的属性描述时触发该操作，比如在执行 {{jsxref("Object.getOwnPropertyDescriptor")}}(proxy, "foo") 时。
-
{{jsxref("Global_Objects/Proxy/handler/defineProperty", "handler.defineProperty()")}}
-
在定义代理对象某个属性时的属性描述时触发该操作，比如在执行 {{jsxref("Object.defineProperty")}}(proxy, "foo", {}) 时。
-
{{jsxref("Global_Objects/Proxy/handler/has", "handler.has()")}}
-
在判断代理对象是否拥有某个属性时触发该操作，比如在执行 "foo" {{jsxref("Operators/in", "in")}} proxy 时。
-
{{jsxref("Global_Objects/Proxy/handler/get", "handler.get()")}}
-
在读取代理对象的某个属性时触发该操作，比如在执行 proxy.foo 时。
-
{{jsxref("Global_Objects/Proxy/handler/set", "handler.set()")}}
-
在给代理对象的某个属性赋值时触发该操作，比如在执行 proxy.foo = 1 时。
-
{{jsxref("Global_Objects/Proxy/handler/deleteProperty", "handler.deleteProperty()")}}
-
在删除代理对象的某个属性时触发该操作，即使用 {{jsxref("Operators/delete", "delete")}} 运算符，比如在执行 delete proxy.foo 时。
-
{{jsxref("Global_Objects/Proxy/handler/ownKeys", "handler.ownKeys()")}}
-
{{jsxref("Object.getOwnPropertyNames")}} 和{{jsxref("Object.getOwnPropertySymbols")}} 的陷阱。
-
{{jsxref("Global_Objects/Proxy/handler/apply", "handler.apply()")}}
-
函数调用操作的陷阱。
-
{{jsxref("Global_Objects/Proxy/handler/construct", "handler.construct()")}}
-
{{jsxref("Operators/new", "new")}} 运算符的陷阱。
-
- -

一些不标准的陷阱已经废弃并且被移除了

- -

规范

- - - - - - - - - - -
规范
{{SpecName('ESDraft', '#sec-proxy-object-internal-methods-and-internal-slots', 'Proxy Object Internal Methods and Internal Slots')}}
- -

浏览器兼容性

- - - -

{{Compat("javascript.builtins.Proxy.handler")}}

- -

相关链接

- - diff --git a/files/zh-cn/web/javascript/reference/global_objects/proxy/handler/isextensible/index.html b/files/zh-cn/web/javascript/reference/global_objects/proxy/handler/isextensible/index.html deleted file mode 100644 index 7be418197f..0000000000 --- a/files/zh-cn/web/javascript/reference/global_objects/proxy/handler/isextensible/index.html +++ /dev/null @@ -1,123 +0,0 @@ ---- -title: handler.isExtensible() -slug: Web/JavaScript/Reference/Global_Objects/Proxy/handler/isExtensible -tags: - - ECMAScript 2015 - - JavaScript - - Method - - Proxy -translation_of: Web/JavaScript/Reference/Global_Objects/Proxy/Proxy/isExtensible ---- -
{{JSRef}}
-handler.isExtensible() 方法用于拦截对对象的Object.isExtensible()。
- -
-

{{EmbedInteractiveExample("pages/js/proxyhandler-isextensible.html", "taller")}}

-
- -

语法

- -
var p = new Proxy(target, {
-  isExtensible: function(target) {
-  }
-});
-
- -

参数

- -

下列参数将会被传递给 isExtensible方法。 this 绑定在 handler 对象上。

- -
-
target
-
目标对象。
-
- -

返回值

- -

isExtensible方法必须返回一个 Boolean值或可转换成Boolean的值。

- -

描述

- -

handler.isExtensible()用于拦截对对象的Object.isExtensible()。

- -

拦截

- -

该方法会拦截目标对象的以下操作:

- - - -

约束

- -

如果违背了以下的约束，proxy会抛出 TypeError:

- - - -

示例

- -

以下代码演示{{jsxref("Object.isExtensible()")}}.

- -
var p = new Proxy({}, {
-  isExtensible: function(target) {
-    console.log('called');
-    return true;//也可以return 1;等表示为true的值
-  }
-});
-
-console.log(Object.isExtensible(p)); // "called"
-                                     // true
-
- -

以下代码演示违反约束的情况。

- -
var p = new Proxy({}, {
-  isExtensible: function(target) {
-    return false;//return 0;return NaN等都会报错
-  }
-});
-
-Object.isExtensible(p); // TypeError is thrown
-
- -

规范

- - - - - - - - - - - - - - - - - - - -
SpecificationStatusComment
{{SpecName('ES2015', '#sec-proxy-object-internal-methods-and-internal-slots-isextensible', '[[IsExtensible]]')}}{{Spec2('ES2015')}}Initial definition.
{{SpecName('ESDraft', '#sec-proxy-object-internal-methods-and-internal-slots-isextensible', '[[IsExtensible]]')}}{{Spec2('ESDraft')}}
- -

浏览器兼容性

- -
- - -

{{Compat("javascript.builtins.Proxy.handler.isExtensible")}}

-
- -

另见

- - diff --git a/files/zh-cn/web/javascript/reference/global_objects/proxy/handler/ownkeys/index.html b/files/zh-cn/web/javascript/reference/global_objects/proxy/handler/ownkeys/index.html deleted file mode 100644 index 956b908375..0000000000 --- a/files/zh-cn/web/javascript/reference/global_objects/proxy/handler/ownkeys/index.html +++ /dev/null @@ -1,193 +0,0 @@ ---- -title: handler.ownKeys() -slug: Web/JavaScript/Reference/Global_Objects/Proxy/handler/ownKeys -translation_of: Web/JavaScript/Reference/Global_Objects/Proxy/Proxy/ownKeys ---- -
{{JSRef}}
- -

handler.ownKeys() 方法用于拦截 {{jsxref("Reflect.ownKeys()")}}.

- - - -

{{EmbedInteractiveExample("pages/js/proxyhandler-ownkeys.html", "taller")}}

- - - -

语法

- -
var p = new Proxy(target, {
-  ownKeys: function(target) {
-  }
-});
-
- -

参数

- -

下面的参数被传递给ownKeys。this被绑定在handler上。

- -
-
target
-
目标对象.
-
- -

返回值

- -

ownKeys 方法必须返回一个可枚举对象.

- -

描述

- -

handler.ownKeys() 方法用于拦截 {{jsxref("Reflect.ownKeys()")}}.

- -

拦截

- -

该拦截器可以拦截以下操作::

- - - -

约束

- -

如果违反了下面的约束，proxy将抛出错误 {{jsxref("TypeError")}}:

- - - -

示例

- -

下面的代码拦截 {{jsxref("Object.getOwnPropertyNames()")}}.

- -
var p = new Proxy({}, {
-  ownKeys: function(target) {
-    console.log('called');
-    return ['a', 'b', 'c'];
-  }
-});
-
-console.log(Object.getOwnPropertyNames(p)); // "called"
-                                            // [ 'a', 'b', 'c' ]
- -

下面的代码违反了约定

- -
var obj = {};
-Object.defineProperty(obj, 'a', {
-  configurable: false,
-  enumerable: true,
-  value: 10 }
-);
-
-var p = new Proxy(obj, {
-  ownKeys: function(target) {
-    return [123, 12.5, true, false, undefined, null, {}, []];
-  }
-});
-
-console.log(Object.getOwnPropertyNames(p));
-
-// TypeError: proxy [[OwnPropertyKeys]] 必须返回一个数组
-// 数组元素类型只能是String或Symbol
-
- -

标准

- - - - - - - - - - - - - - - - - - - -
SpecificationStatusComment
{{SpecName('ES2015', '#sec-proxy-object-internal-methods-and-internal-slots-ownpropertykeys', '[[OwnPropertyKeys]]')}}{{Spec2('ES2015')}}Initial definition.
{{SpecName('ESDraft', '#sec-proxy-object-internal-methods-and-internal-slots-ownpropertykeys', '[[OwnPropertyKeys]]')}}{{Spec2('ESDraft')}}
- -

浏览器兼容

- -
{{CompatibilityTable}}
- -
- - - - - - - - - - - - - - - - - - - -
FeatureChromeFirefox (Gecko)Internet ExplorerOperaSafari
Basic support{{CompatUnknown}}{{CompatGeckoDesktop("18")}}{{CompatUnknown}}{{CompatUnknown}}{{CompatUnknown}}
-
- -
- - - - - - - - - - - - - - - - - - - - - -
FeatureAndroidChrome for AndroidFirefox Mobile (Gecko)IE MobileOpera MobileSafari Mobile
Basic support{{CompatUnknown}}{{CompatUnknown}}{{CompatGeckoMobile("18")}}{{CompatUnknown}}{{CompatUnknown}}{{CompatUnknown}}
-
- -

兼容性注意事项

- -

Firefox火狐

- - - -

另见

- - diff --git a/files/zh-cn/web/javascript/reference/global_objects/proxy/handler/preventextensions/index.html b/files/zh-cn/web/javascript/reference/global_objects/proxy/handler/preventextensions/index.html deleted file mode 100644 index dd6823c9dd..0000000000 --- a/files/zh-cn/web/javascript/reference/global_objects/proxy/handler/preventextensions/index.html +++ /dev/null @@ -1,120 +0,0 @@ ---- -title: handler.preventExtensions() -slug: Web/JavaScript/Reference/Global_Objects/Proxy/handler/preventExtensions -tags: - - Proxy 代理 拦截 -translation_of: Web/JavaScript/Reference/Global_Objects/Proxy/Proxy/preventExtensions ---- -
{{JSRef}}
- -

handler.preventExtensions() 方法用于设置对{{jsxref("Object.preventExtensions()")}}的拦截

- -

{{EmbedInteractiveExample("pages/js/proxyhandler-preventextensions.html", "taller")}}

- -

语法

- -
var p = new Proxy(target, {
-  preventExtensions: function(target) {
-  }
-});
-
- -

参数

- -

以下参数传递给 preventExtensions 方法. 它会绑定到这个handler.

- -
-
target
-
所要拦截的目标对象.
-
- -

返回值

- -

preventExtensions 方法返回一个布尔值.

- -

描述

- -

handler.preventExtensions() 拦截 {{jsxref("Object.preventExtensions()")}}返回一个布尔值.

- -

拦截

- -

这个trap可以拦截这些操作:

- - - -

约束

- -

如果违反了下列规则, proxy则会抛出一个 {{jsxref("TypeError")}}:

- - - -

示例

- -

以下代码演示了如何拦截{{jsxref("Object.preventExtensions()")}}。

- -
var p = new Proxy({}, {
-  preventExtensions: function(target) {
-    console.log('called');
-    Object.preventExtensions(target);
-    return true;
-  }
-});
-
-console.log(Object.preventExtensions(p)); // "called"
-                                          // false
-
- -

以下代码违反了约束.

- -
var p = new Proxy({}, {
-  preventExtensions: function(target) {
-    return true;
-  }
-});
-
-Object.preventExtensions(p); // 抛出类型错误
-
- -

规范

- - - - - - - - - - - - - - - - - - - -
SpecificationStatusComment
{{SpecName('ES2015', '#sec-proxy-object-internal-methods-and-internal-slots-preventextensions', '[[PreventExtensions]]')}}{{Spec2('ES2015')}}Initial definition.
{{SpecName('ESDraft', '#sec-proxy-object-internal-methods-and-internal-slots-preventextensions', '[[PreventExtensions]]')}}{{Spec2('ESDraft')}}
- -

浏览器兼容性

- -
- - -

{{Compat("javascript.builtins.Proxy.handler.preventExtensions")}}

-
- -

参考

- - diff --git a/files/zh-cn/web/javascript/reference/global_objects/proxy/handler/set/index.html b/files/zh-cn/web/javascript/reference/global_objects/proxy/handler/set/index.html deleted file mode 100644 index c66481647a..0000000000 --- a/files/zh-cn/web/javascript/reference/global_objects/proxy/handler/set/index.html +++ /dev/null @@ -1,125 +0,0 @@ ---- -title: handler.set() -slug: Web/JavaScript/Reference/Global_Objects/Proxy/handler/set -tags: - - ECMAScript6 - - JavaScript - - Method - - Proxy - - Proxy拦截 -translation_of: Web/JavaScript/Reference/Global_Objects/Proxy/Proxy/set ---- -
{{JSRef}}
- -

handler.set() 方法是设置属性值操作的捕获器。

- -
{{EmbedInteractiveExample("pages/js/proxyhandler-set.html", "taller")}}
- - - -

语法

- -
const p = new Proxy(target, {
-  set: function(target, property, value, receiver) {
-  }
-});
-
- -

参数

- -

以下是传递给 set() 方法的参数。this 绑定在 handler 对象上。

- -
-
target
-
目标对象。
-
property
-
将被设置的属性名或 {{jsxref("Symbol")}}。
-
value
-
新属性值。
-
receiver
-
最初被调用的对象。通常是 proxy 本身，但 handler 的 set 方法也有可能在原型链上，或以其他方式被间接地调用（因此不一定是 proxy 本身）。 -
-

比如：假设有一段代码执行 obj.name = "jen"， obj 不是一个 proxy，且自身不含 name 属性，但是它的原型链上有一个 proxy，那么，那个 proxy 的 set() 处理器会被调用，而此时，obj 会作为 receiver 参数传进来。

-
-
-
- -

返回值

- -

set() 方法应当返回一个布尔值。

- - - -

描述

- -

handler.set() 方法用于拦截设置属性值的操作。

- -

拦截

- -

该方法会拦截目标对象的以下操作:

- - - -

约束

- -

如果违背以下的约束条件，proxy 会抛出一个 {{jsxref("TypeError")}} 异常：

- - - -

示例

- -

以下代码演示如何捕获属性的设置操作。

- -
var p = new Proxy({}, {
-  set: function(target, prop, value, receiver) {
-    target[prop] = value;
-    console.log('property set: ' + prop + ' = ' + value);
-    return true;
-  }
-})
-
-console.log('a' in p);  // false
-
-p.a = 10;               // "property set: a = 10"
-console.log('a' in p);  // true
-console.log(p.a);       // 10
- -

规范

- - - - - - - - - - - - -
规范
{{SpecName('ESDraft', '#sec-proxy-object-internal-methods-and-internal-slots-set-p-v-receiver', '[[Set]]')}}
- -

浏览器兼容性

- - - -

{{Compat("javascript.builtins.Proxy.handler.set")}}

- -

另见

- - diff --git a/files/zh-cn/web/javascript/reference/global_objects/proxy/handler/setprototypeof/index.html b/files/zh-cn/web/javascript/reference/global_objects/proxy/handler/setprototypeof/index.html deleted file mode 100644 index 9d88cd2593..0000000000 --- a/files/zh-cn/web/javascript/reference/global_objects/proxy/handler/setprototypeof/index.html +++ /dev/null @@ -1,124 +0,0 @@ ---- -title: handler.setPrototypeOf() -slug: Web/JavaScript/Reference/Global_Objects/Proxy/handler/setPrototypeOf -translation_of: Web/JavaScript/Reference/Global_Objects/Proxy/Proxy/setPrototypeOf ---- -
{{JSRef}}
- -

handler.setPrototypeOf() 方法主要用来拦截 {{jsxref("Object.setPrototypeOf()")}}.

- -

语法

- -
var p = new Proxy(target, {
-  setPrototypeOf: function(target, prototype) {
-  }
-});
-
- -

参数

- -

以下参数传递给 setPrototypeOf 方法. 

- -
-
target
-
被拦截目标对象.
-
prototype
-
对象新原型或为null.
-
- -

返回值

- -

如果成功修改了[[Prototype]], setPrototypeOf 方法返回 true,否则返回 false.

- -

描述

- -

这个 handler.setPrototypeOf 方法用于拦截 {{jsxref("Object.setPrototypeOf()")}}.

- -

拦截

- -

这个方法可以拦截以下操作:

- - - -

Invariants

- -

如果违反了下列规则，则proxy将抛出一个{{jsxref("TypeError")}}:

- - - -

示例

- -

如果你不想为你的对象设置一个新的原型，你的handler's的setPrototypeOf方法可以返回false，也可以抛出异常。

- -

The former approach means that any operation that performs such mutation, that throws an exception on failure to mutate, will have to create the exception itself.  For example, {{jsxref("Object.setPrototypeOf()")}} will create and throw a TypeError itself.  If the mutation is performed by an operation that doesn't ordinarily throw in case of failure, such as {{jsxref("Reflect.setPrototypeOf()")}}, no exception will be thrown.

- -
var handlerReturnsFalse = {
-    setPrototypeOf(target, newProto) {
-        return false;
-    }
-};
-
-var newProto = {}, target = {};
-
-var p1 = new Proxy(target, handlerReturnsFalse);
-Object.setPrototypeOf(p1, newProto); // throws a TypeError
-Reflect.setPrototypeOf(p1, newProto); // returns false
-
- -

The latter approach will cause any operation that attempts to mutate, to throw.  This approach is required if you want even non-throwing operations to throw on failure, or you want to throw a custom exception value.

- -
var handlerThrows = {
-    setPrototypeOf(target, newProto) {
-        throw new Error('custom error');
-    }
-};
-
-var newProto = {}, target = {};
-
-var p2 = new Proxy(target, handlerThrows);
-Object.setPrototypeOf(p2, newProto); // throws new Error("custom error")
-Reflect.setPrototypeOf(p2, newProto); // throws new Error("custom error")
- -

Specifications

- - - - - - - - - - - - - - - - - - - -
SpecificationStatusComment
{{SpecName('ES2015', '#sec-proxy-object-internal-methods-and-internal-slots-setprototypeof-v', '[[SetPrototypeOf]]')}}{{Spec2('ES2015')}}Initial definition.
{{SpecName('ESDraft', '#sec-proxy-object-internal-methods-and-internal-slots-setprototypeof-v', '[[SetPrototypeOf]]')}}{{Spec2('ESDraft')}} 
- -

Browser compatibility

- -
- - -

{{Compat("javascript.builtins.Proxy.handler.setPrototypeOf")}}

-
- -

See also

- - diff --git a/files/zh-cn/web/javascript/reference/global_objects/proxy/proxy/apply/index.html b/files/zh-cn/web/javascript/reference/global_objects/proxy/proxy/apply/index.html new file mode 100644 index 0000000000..62b8b67f5f --- /dev/null +++ b/files/zh-cn/web/javascript/reference/global_objects/proxy/proxy/apply/index.html @@ -0,0 +1,117 @@ +--- +title: handler.apply() +slug: Web/JavaScript/Reference/Global_Objects/Proxy/handler/apply +tags: + - ECMAScript6 + - JavaScript + - Method + - Proxy +translation_of: Web/JavaScript/Reference/Global_Objects/Proxy/Proxy/apply +--- +
{{JSRef}}
+ +

handler.apply() 方法用于拦截函数的调用。

+ +
{{EmbedInteractiveExample("pages/js/proxyhandler-apply.html", "taller")}}
+ + + +

语法

+ +
var p = new Proxy(target, {
+  apply: function(target, thisArg, argumentsList) {
+  }
+});
+
+ +

参数

+ +

以下是传递给apply方法的参数，this上下文绑定在handler对象上.

+ +
+
target
+
目标对象（函数）。
+
thisArg
+
被调用时的上下文对象。
+
argumentsList
+
被调用时的参数数组。
+
+ +

返回值

+ +

apply方法可以返回任何值。

+ +

描述

+ +

handler.apply 方法用于拦截函数的调用。

+ +

拦截

+ +

该方法会拦截目标对象的以下操作:

+ + + +

约束

+ +

如果违反了以下约束，代理将抛出一个TypeError：

+ +

target必须是可被调用的。也就是说，它必须是一个函数对象。

+ +

示例

+ +

以下代码演示如何捕获函数的调用。

+ +
var p = new Proxy(function() {}, {
+  apply: function(target, thisArg, argumentsList) {
+    console.log('called: ' + argumentsList.join(', '));
+    return argumentsList[0] + argumentsList[1] + argumentsList[2];
+  }
+});
+
+console.log(p(1, 2, 3)); // "called: 1, 2, 3"
+                         // 6
+
+ +

规范

+ + + + + + + + + + + + + + + + + + + +
SpecificationStatusComment
{{SpecName('ES2015', '#sec-proxy-object-internal-methods-and-internal-slots-call-thisargument-argumentslist', '[[Call]]')}}{{Spec2('ES2015')}}Initial definition.
{{SpecName('ESDraft', '#sec-proxy-object-internal-methods-and-internal-slots-call-thisargument-argumentslist', '[[Call]]')}}{{Spec2('ESDraft')}} 
+ +

浏览器兼容性

+ +
+ + +

{{Compat("javascript.builtins.Proxy.handler.apply")}}

+
+ +

另见

+ + diff --git a/files/zh-cn/web/javascript/reference/global_objects/proxy/proxy/construct/index.html b/files/zh-cn/web/javascript/reference/global_objects/proxy/proxy/construct/index.html new file mode 100644 index 0000000000..209e9752e3 --- /dev/null +++ b/files/zh-cn/web/javascript/reference/global_objects/proxy/proxy/construct/index.html @@ -0,0 +1,130 @@ +--- +title: handler.construct() +slug: Web/JavaScript/Reference/Global_Objects/Proxy/handler/construct +translation_of: Web/JavaScript/Reference/Global_Objects/Proxy/Proxy/construct +--- +
{{JSRef}}
+ +

handler.construct() 方法用于拦截{{jsxref("Operators/new", "new")}} 操作符. 为了使new操作符在生成的Proxy对象上生效，用于初始化代理的目标对象自身必须具有[[Construct]]内部方法（即 new target 必须是有效的）。

+ +

{{EmbedInteractiveExample("pages/js/proxyhandler-construct.html", "taller")}}

+ +

语法

+ +
var p = new Proxy(target, {
+  construct: function(target, argumentsList, newTarget) {
+  }
+});
+
+ +

参数

+ +

下面的参数将会传递给construct方法，this绑定在handler上。

+ +
+
target
+
目标对象。
+
argumentsList
+
constructor的参数列表。
+
newTarget
+
最初被调用的构造函数，就上面的例子而言是p。
+
+ +

返回值

+ +

construct 方法必须返回一个对象。

+ +

描述

+ +

handler.construct() 方法用于拦截 {{jsxref("Operators/new", "new")}}操作符。

+ +

拦截

+ +

该拦截器可以拦截以下操作:

+ + + +

约束

+ +

如果违反以下约定，代理将会抛出错误 {{jsxref("TypeError")}}:

+ + + +

示例

+ +

下面代码演示如何拦截 {{jsxref("Operators/new", "new")}} 操作。

+ +
var p = new Proxy(function() {}, {
+  construct: function(target, argumentsList, newTarget) {
+    console.log('called: ' + argumentsList.join(', '));
+    return { value: argumentsList[0] * 10 };
+  }
+});
+
+console.log(new p(1).value); // "called: 1"
+                             // 10
+
+ +

下面的代码违反了约定.

+ +
var p = new Proxy(function() {}, {
+  construct: function(target, argumentsList, newTarget) {
+    return 1;
+  }
+});
+
+new p(); // TypeError is thrown
+
+ +

下面的代码未能正确的初始化Proxy。Proxy初始化时，传给它的target 必须具有一个有效的constructor供new操作符调用。

+ +
var p = new Proxy({}, {
+  construct: function(target, argumentsList, newTarget) {
+    return {};
+  }
+});
+
+new p(); // TypeError is thrown, "p" is not a constructor
+
+ +

规范

+ + + + + + + + + + + + + + + + + + + +
SpecificationStatusComment
{{SpecName('ES2015', '#sec-proxy-object-internal-methods-and-internal-slots-construct-argumentslist-newtarget', '[[Construct]]')}}{{Spec2('ES2015')}}Initial definition.
{{SpecName('ESDraft', '#sec-proxy-object-internal-methods-and-internal-slots-construct-argumentslist-newtarget', '[[Construct]]')}}{{Spec2('ESDraft')}} 
+ +

浏览器兼容性

+ +
{{Compat("javascript.builtins.Proxy.handler.construct")}}
+ +
 
+ +

相关主题

+ + diff --git a/files/zh-cn/web/javascript/reference/global_objects/proxy/proxy/defineproperty/index.html b/files/zh-cn/web/javascript/reference/global_objects/proxy/proxy/defineproperty/index.html new file mode 100644 index 0000000000..9912e043a0 --- /dev/null +++ b/files/zh-cn/web/javascript/reference/global_objects/proxy/proxy/defineproperty/index.html @@ -0,0 +1,181 @@ +--- +title: handler.defineProperty() +slug: Web/JavaScript/Reference/Global_Objects/Proxy/handler/defineProperty +translation_of: Web/JavaScript/Reference/Global_Objects/Proxy/Proxy/defineProperty +--- +
{{JSRef}}
+ +

handler.defineProperty() 用于拦截对对象的 {{jsxref("Object.defineProperty()")}} 操作。

+ +

语法

+ +
var p = new Proxy(target, {
+  defineProperty: function(target, property, descriptor) {
+  }
+});
+
+ +

参数

+ +

下列参数将会被传递给 defineProperty 方法。 this 绑定在 handler 对象上。

+ +
+
target
+
目标对象。
+
property
+
待检索其描述的属性名。
+
descriptor
+
待定义或修改的属性的描述符。
+
+ +

返回值

+ +

defineProperty 方法必须以一个 {{jsxref("Boolean")}} 返回，表示定义该属性的操作成功与否。

+ +

描述

+ +

handler.defineProperty() 用于拦截对对象的 {{jsxref("Object.defineProperty()")}} 操作。

+ +

拦截

+ +

该方法会拦截目标对象的以下操作 :

+ + + +

不变量

+ +

如果违背了以下的不变量，proxy会抛出 {{jsxref("TypeError")}}:

+ + + +

示例

+ +

以下代码演示如何拦截对目标对象的 {{jsxref("Object.defineProperty()")}} 操作。

+ +
var p = new Proxy({}, {
+  defineProperty: function(target, prop, descriptor) {
+    console.log('called: ' + prop);
+    return true;
+  }
+});
+
+var desc = { configurable: true, enumerable: true, value: 10 };
+Object.defineProperty(p, 'a', desc); // "called: a"
+
+ +

当调用 {{jsxref("Object.defineProperty()")}} 或者 {{jsxref("Reflect.defineProperty()")}}，传递给 defineProperty 的 descriptor   有一个限制 - 只有以下属性才有用，非标准的属性将会被无视 :

+ + + +
var p = new Proxy({}, {
+  defineProperty(target, prop, descriptor) {
+    console.log(descriptor);
+    return Reflect.defineProperty(target, prop, descriptor);
+  }
+});
+
+Object.defineProperty(p, 'name', {
+  value: 'proxy',
+  type: 'custom'
+});  // { value: 'proxy' }
+
+ +

规范

+ + + + + + + + + + + + + + + + + + + +
SpecificationStatusComment
{{SpecName('ES2015', '#sec-proxy-object-internal-methods-and-internal-slots-defineownproperty-p-desc', '[[DefineOwnProperty]]')}}{{Spec2('ES2015')}}Initial definition.
{{SpecName('ESDraft', '#sec-proxy-object-internal-methods-and-internal-slots-defineownproperty-p-desc', '[[DefineOwnProperty]]')}}{{Spec2('ESDraft')}}
+ +

浏览器兼容性

+ +
{{CompatibilityTable}}
+ +
+ + + + + + + + + + + + + + + + + + + +
FeatureChromeFirefox (Gecko)Internet ExplorerOperaSafari
Basic support{{CompatUnknown}}{{CompatGeckoDesktop("18")}}{{CompatUnknown}}{{CompatUnknown}}{{CompatUnknown}}
+
+ +
+ + + + + + + + + + + + + + + + + + + + + +
FeatureAndroidChrome for AndroidFirefox Mobile (Gecko)IE MobileOpera MobileSafari Mobile
Basic support{{CompatUnknown}}{{CompatUnknown}}{{CompatGeckoMobile("18")}}{{CompatUnknown}}{{CompatUnknown}}{{CompatUnknown}}
+
+ +

另见

+ + diff --git a/files/zh-cn/web/javascript/reference/global_objects/proxy/proxy/deleteproperty/index.html b/files/zh-cn/web/javascript/reference/global_objects/proxy/proxy/deleteproperty/index.html new file mode 100644 index 0000000000..6cb4255755 --- /dev/null +++ b/files/zh-cn/web/javascript/reference/global_objects/proxy/proxy/deleteproperty/index.html @@ -0,0 +1,149 @@ +--- +title: handler.deleteProperty() +slug: Web/JavaScript/Reference/Global_Objects/Proxy/handler/deleteProperty +translation_of: Web/JavaScript/Reference/Global_Objects/Proxy/Proxy/deleteProperty +--- +
{{JSRef}}
+ +

handler.deleteProperty() 方法用于拦截对对象属性的 {{jsxref("Operators/delete", "delete")}} 操作。

+ +

语法

+ +
var p = new Proxy(target, {
+  deleteProperty: function(target, property) {
+  }
+});
+
+ +

参数

+ +

deleteProperty 方法将会接受以下参数。 this 被绑定在 handler上。

+ +
+
target
+
目标对象。
+
property
+
待删除的属性名。
+
+ +

返回值

+ +

deleteProperty 必须返回一个 {{jsxref("Boolean")}} 类型的值，表示了该属性是否被成功删除。

+ +

描述

+ +

handler.deleteProperty() 方法可以拦截 {{jsxref("Operators/delete", "delete")}} 操作。

+ +

拦截

+ +

该方法会拦截以下操作:

+ + + +

不变量

+ +

如果违背了以下不变量，proxy 将会抛出一个 {{jsxref("TypeError")}}:

+ + + +

示例

+ +

以下代码演示了对 {{jsxref("Operators/delete", "delete")}} 操作的拦截。

+ +
var p = new Proxy({}, {
+  deleteProperty: function(target, prop) {
+    console.log('called: ' + prop);
+    return true;
+  }
+});
+
+delete p.a; // "called: a"
+
+ +

规范

+ + + + + + + + + + + + + + + + + + + +
SpecificationStatusComment
{{SpecName('ES2015', '#sec-proxy-object-internal-methods-and-internal-slots-delete-p', '[[Delete]]')}}{{Spec2('ES2015')}}Initial definition.
{{SpecName('ESDraft', '#sec-proxy-object-internal-methods-and-internal-slots-delete-p', '[[Delete]]')}}{{Spec2('ESDraft')}} 
+ +

浏览器兼容性

+ +
{{CompatibilityTable}}
+ +
+ + + + + + + + + + + + + + + + + + + +
FeatureChromeFirefox (Gecko)Internet ExplorerOperaSafari
Basic support{{CompatUnknown}}{{CompatGeckoDesktop("18")}}{{CompatUnknown}}{{CompatUnknown}}{{CompatUnknown}}
+
+ +
+ + + + + + + + + + + + + + + + + + + + + +
FeatureAndroidChrome for AndroidFirefox Mobile (Gecko)IE MobileOpera MobileSafari Mobile
Basic support{{CompatUnknown}}{{CompatUnknown}}{{CompatGeckoMobile("18")}}{{CompatUnknown}}{{CompatUnknown}}{{CompatUnknown}}
+
+ +

另见

+ + diff --git a/files/zh-cn/web/javascript/reference/global_objects/proxy/proxy/get/index.html b/files/zh-cn/web/javascript/reference/global_objects/proxy/proxy/get/index.html new file mode 100644 index 0000000000..14a350436a --- /dev/null +++ b/files/zh-cn/web/javascript/reference/global_objects/proxy/proxy/get/index.html @@ -0,0 +1,177 @@ +--- +title: handler.get() +slug: Web/JavaScript/Reference/Global_Objects/Proxy/handler/get +tags: + - ECMAScript6 + - JavaScript + - Method + - Proxy +translation_of: Web/JavaScript/Reference/Global_Objects/Proxy/Proxy/get +--- +
{{JSRef}}
+ +

handler.get() 方法用于拦截对象的读取属性操作。

+ +

语法

+ +
var p = new Proxy(target, {
+  get: function(target, property, receiver) {
+  }
+});
+
+ +

参数

+ +

以下是传递给get方法的参数，this上下文绑定在handler对象上.

+ +
+
target
+
目标对象。
+
property
+
被获取的属性名。
+
receiver
+
Proxy或者继承Proxy的对象
+
+ +

返回值

+ +

get方法可以返回任何值。

+ +

描述

+ +

handler.get 方法用于拦截对象的读取属性操作。

+ +

拦截

+ +

该方法会拦截目标对象的以下操作:

+ + + +

约束

+ +

如果违背了以下的约束，proxy会抛出 {{jsxref("TypeError")}}:

+ + + +

示例

+ +

以下代码演示如何拦截属性值的读取操作。

+ +
var p = new Proxy({}, {
+  get: function(target, prop, receiver) {
+    console.log("called: " + prop);
+    return 10;
+  }
+});
+
+console.log(p.a); // "called: a"
+                  // 10
+
+ +

以下代码演示违反约束的情况。

+ +
var obj = {};
+Object.defineProperty(obj, "a", {
+  configurable: false,
+  enumerable: false,
+  value: 10,
+  writable: false
+});
+
+var p = new Proxy(obj, {
+  get: function(target, prop) {
+    return 20;
+  }
+});
+
+p.a; //会抛出TypeError
+
+ +

规范

+ + + + + + + + + + + + + + + + + + + +
SpecificationStatusComment
{{SpecName('ES2015', '#sec-proxy-object-internal-methods-and-internal-slots-get-p-receiver', '[[Get]]')}}{{Spec2('ES2015')}}Initial definition.
{{SpecName('ESDraft', '#sec-proxy-object-internal-methods-and-internal-slots-get-p-receiver', '[[Get]]')}}{{Spec2('ESDraft')}} 
+ +

浏览器兼容性

+ +
{{CompatibilityTable}}
+ +
+ + + + + + + + + + + + + + + + + + + +
FeatureChromeFirefox (Gecko)Internet ExplorerOperaSafari
Basic support{{CompatUnknown}}{{CompatGeckoDesktop("18")}}{{CompatUnknown}}{{CompatUnknown}}{{CompatUnknown}}
+
+ +
+ + + + + + + + + + + + + + + + + + + + + +
FeatureAndroidChrome for AndroidFirefox Mobile (Gecko)IE MobileOpera MobileSafari Mobile
Basic support{{CompatUnknown}}{{CompatUnknown}}{{CompatGeckoMobile("18")}}{{CompatUnknown}}{{CompatUnknown}}{{CompatUnknown}}
+
+ +

另见

+ + diff --git a/files/zh-cn/web/javascript/reference/global_objects/proxy/proxy/getownpropertydescriptor/index.html b/files/zh-cn/web/javascript/reference/global_objects/proxy/proxy/getownpropertydescriptor/index.html new file mode 100644 index 0000000000..470b2c6ad9 --- /dev/null +++ b/files/zh-cn/web/javascript/reference/global_objects/proxy/proxy/getownpropertydescriptor/index.html @@ -0,0 +1,168 @@ +--- +title: handler.getOwnPropertyDescriptor() +slug: Web/JavaScript/Reference/Global_Objects/Proxy/handler/getOwnPropertyDescriptor +translation_of: Web/JavaScript/Reference/Global_Objects/Proxy/Proxy/getOwnPropertyDescriptor +--- +
{{JSRef}}
+ +

handler.getOwnPropertyDescriptor() 方法是 {{jsxref("Object.getOwnPropertyDescriptor()")}}  的钩子。

+ +

语法

+ +
var p = new Proxy(target, {
+  getOwnPropertyDescriptor: function(target, prop) {
+  }
+});
+
+ +

参数

+ +

下列参数会被传入 getOwnPropertyDescriptor 方法中。这是绑定到handler上。 

+ +
+
target
+
目标对象。
+
prop
+
返回属性名称的描述。
+
+ +

返回值

+ +

getOwnPropertyDescriptor 方法必须返回一个 object 或 undefined。

+ +

描述

+ +

handler.getOwnPropertyDescriptor() 方法是 {{jsxref("Object.getOwnPropertyDescriptor()")}} 的陷阱。

+ +

拦截

+ +

这个陷阱可以拦截这些操作：

+ + + +

不变量

+ +

如果下列不变量被违反，代理将抛出一个 {{jsxref("TypeError")}}：

+ + + +

示例

+ +

以下是 {{jsxref("Object.getOwnPropertyDescriptor()")}} 的代码陷阱：

+ +
var p = new Proxy({ a: 20}, {
+  getOwnPropertyDescriptor: function(target, prop) {
+    console.log('called: ' + prop);
+    return { configurable: true, enumerable: true, value: 10 };
+  }
+});
+
+console.log(Object.getOwnPropertyDescriptor(p, 'a').value); // "called: a"
+                                                            // 10
+
+ +

以下代码则违反了不变量。

+ +
var obj = { a: 10 };
+Object.preventExtensions(obj);
+var p = new Proxy(obj, {
+  getOwnPropertyDescriptor: function(target, prop) {
+    return undefined;
+  }
+});
+
+Object.getOwnPropertyDescriptor(p, 'a'); // TypeError is thrown
+
+ +

规范

+ + + + + + + + + + + + + + + + + + + +
SpecificationStatusComment
{{SpecName('ES2015', '#sec-proxy-object-internal-methods-and-internal-slots-getownproperty-p', '[[GetOwnProperty]]')}}{{Spec2('ES2015')}}Initial definition.
{{SpecName('ESDraft', '#sec-proxy-object-internal-methods-and-internal-slots-getownproperty-p', '[[GetOwnProperty]]')}}{{Spec2('ESDraft')}}
+ +

浏览器兼容性

+ +
{{CompatibilityTable}}
+ +
+ + + + + + + + + + + + + + + + + + + +
FeatureChromeFirefox (Gecko)Internet ExplorerOperaSafari
Basic support{{CompatUnknown}}{{CompatGeckoDesktop("18")}}{{CompatUnknown}}{{CompatUnknown}}{{CompatUnknown}}
+
+ +
+ + + + + + + + + + + + + + + + + + + + + +
FeatureAndroidChrome for AndroidFirefox Mobile (Gecko)IE MobileOpera MobileSafari Mobile
Basic support{{CompatUnknown}}{{CompatUnknown}}{{CompatGeckoMobile("18")}}{{CompatUnknown}}{{CompatUnknown}}{{CompatUnknown}}
+
+ +

相关链接

+ + diff --git a/files/zh-cn/web/javascript/reference/global_objects/proxy/proxy/getprototypeof/index.html b/files/zh-cn/web/javascript/reference/global_objects/proxy/proxy/getprototypeof/index.html new file mode 100644 index 0000000000..215d2d9646 --- /dev/null +++ b/files/zh-cn/web/javascript/reference/global_objects/proxy/proxy/getprototypeof/index.html @@ -0,0 +1,141 @@ +--- +title: handler.getPrototypeOf() +slug: Web/JavaScript/Reference/Global_Objects/Proxy/handler/getPrototypeOf +tags: + - ECMAScript 2015 + - JavaScript + - Method + - Proxy + - 方法 +translation_of: Web/JavaScript/Reference/Global_Objects/Proxy/Proxy/getPrototypeOf +--- +
{{JSRef("Global_Objects", "Proxy")}}
+ +

handler.getPrototypeOf() 是一个代理（Proxy）方法，当读取代理对象的原型时，该方法就会被调用。

+ +
{{EmbedInteractiveExample("pages/js/proxyhandler-getprototypeof.html", "taller")}}
+ + + +

语法

+ +
const p = new Proxy(obj, {
+  getPrototypeOf(target) {
+  ...
+  }
+});
+
+ +

参数

+ +

当 getPrototypeOf 方法被调用时，this 指向的是它所属的处理器对象。

+ +
+
target
+
被代理的目标对象。
+
+ +

返回值

+ +

getPrototypeOf 方法的返回值必须是一个对象或者 null。

+ +

描述

+ +

在 JavaScript 中，下面这五种操作（方法/属性/运算符）可以触发 JS 引擎读取一个对象的原型，也就是可以触发 getPrototypeOf() 代理方法的运行：

+ + + +

如果遇到了下面两种情况，JS 引擎会抛出 {{jsxref("TypeError")}} 异常：

+ + + +

示例

+ +

基本用法

+ +
var obj = {};
+var proto = {};
+var handler = {
+    getPrototypeOf(target) {
+        console.log(target === obj);   // true
+        console.log(this === handler); // true
+        return proto;
+    }
+};
+
+var p = new Proxy(obj, handler);
+console.log(Object.getPrototypeOf(p) === proto);    // true
+
+ +

5 种触发 getPrototypeOf 代理方法的方式

+ +
var obj = {};
+var p = new Proxy(obj, {
+    getPrototypeOf(target) {
+        return Array.prototype;
+    }
+});
+console.log(
+    Object.getPrototypeOf(p) === Array.prototype,  // true
+    Reflect.getPrototypeOf(p) === Array.prototype, // true
+    p.__proto__ === Array.prototype,               // true
+    Array.prototype.isPrototypeOf(p),              // true
+    p instanceof Array                             // true
+);
+
+ +

两种情况下的异常

+ +
var obj = {};
+var p = new Proxy(obj, {
+    getPrototypeOf(target) {
+        return "foo";
+    }
+});
+Object.getPrototypeOf(p); // TypeError: "foo" is not an object or null
+
+var obj = Object.preventExtensions({});
+var p = new Proxy(obj, {
+    getPrototypeOf(target) {
+        return {};
+    }
+});
+Object.getPrototypeOf(p); // TypeError: expected same prototype value
+
+ +

规范

+ + + + + + + + + + +
规范
{{SpecName('ESDraft', '#sec-proxy-object-internal-methods-and-internal-slots-getprototypeof', '[[GetPrototypeOf]]')}}
+ +

浏览器兼容性

+ + + +

{{Compat("javascript.builtins.Proxy.handler.getPrototypeOf")}}

+ +

参见

+ + diff --git a/files/zh-cn/web/javascript/reference/global_objects/proxy/proxy/has/index.html b/files/zh-cn/web/javascript/reference/global_objects/proxy/proxy/has/index.html new file mode 100644 index 0000000000..fead0846ff --- /dev/null +++ b/files/zh-cn/web/javascript/reference/global_objects/proxy/proxy/has/index.html @@ -0,0 +1,176 @@ +--- +title: handler.has() +slug: Web/JavaScript/Reference/Global_Objects/Proxy/handler/has +translation_of: Web/JavaScript/Reference/Global_Objects/Proxy/Proxy/has +--- +
{{JSRef}}
+ +

 handler.has() 方法是针对 {{jsxref("Operators/in", "in")}} 操作符的代理方法。

+ + + + + +

{{EmbedInteractiveExample("pages/js/proxyhandler-has.html", "taller")}}

+ + + + + +

语法

+ +
var p = new Proxy(target, {
+  has: function(target, prop) {
+  }
+});
+
+ +

参数

+ +

下面是传递给 has 方法的参数. this is bound to the handler.

+ +
+
target
+
目标对象.
+
prop
+
需要检查是否存在的属性.
+
+ +

返回值

+ +

has 方法返回一个 boolean 属性的值.

+ +

描述

+ +

handler.has 方法可以看作是针对 {{jsxref("Operators/in", "in")}} 操作的钩子.

+ +

拦截

+ +

这个钩子可以拦截下面这些操作:

+ + + +

约束

+ +

如果违反了下面这些规则,  proxy 将会抛出 {{jsxref("TypeError")}}:

+ + + +

示例

+ +

下面的代码拦截了 {{jsxref("Operators/in", "in")}} 操作符.

+ +
var p = new Proxy({}, {
+  has: function(target, prop) {
+    console.log('called: ' + prop);
+    return true;
+  }
+});
+
+console.log('a' in p); // "called: a"
+                       // true
+
+ +

下面的代码违反了约束.

+ +
var obj = { a: 10 };
+Object.preventExtensions(obj);
+var p = new Proxy(obj, {
+  has: function(target, prop) {
+    return false;
+  }
+});
+
+'a' in p; // TypeError is thrown
+
+ +

规范

+ + + + + + + + + + + + + + + + + + + +
SpecificationStatusComment
{{SpecName('ES2015', '#sec-proxy-object-internal-methods-and-internal-slots-hasproperty-p', '[[HasProperty]]')}}{{Spec2('ES2015')}}Initial definition.
{{SpecName('ESDraft', '#sec-proxy-object-internal-methods-and-internal-slots-hasproperty-p', '[[HasProperty]]')}}{{Spec2('ESDraft')}}
+ +

浏览器支持

+ +
{{CompatibilityTable}}
+ +
+ + + + + + + + + + + + + + + + + + + +
FeatureChromeFirefox (Gecko)Internet ExplorerOperaSafari
Basic support{{CompatUnknown}}{{CompatGeckoDesktop("18")}}{{CompatUnknown}}{{CompatUnknown}}{{CompatUnknown}}
+
+ +
+ + + + + + + + + + + + + + + + + + + + + +
FeatureAndroidChrome for AndroidFirefox Mobile (Gecko)IE MobileOpera MobileSafari Mobile
Basic support{{CompatUnknown}}{{CompatUnknown}}{{CompatGeckoMobile("18")}}{{CompatUnknown}}{{CompatUnknown}}{{CompatUnknown}}
+
+ +

其他

+ + diff --git a/files/zh-cn/web/javascript/reference/global_objects/proxy/proxy/isextensible/index.html b/files/zh-cn/web/javascript/reference/global_objects/proxy/proxy/isextensible/index.html new file mode 100644 index 0000000000..7be418197f --- /dev/null +++ b/files/zh-cn/web/javascript/reference/global_objects/proxy/proxy/isextensible/index.html @@ -0,0 +1,123 @@ +--- +title: handler.isExtensible() +slug: Web/JavaScript/Reference/Global_Objects/Proxy/handler/isExtensible +tags: + - ECMAScript 2015 + - JavaScript + - Method + - Proxy +translation_of: Web/JavaScript/Reference/Global_Objects/Proxy/Proxy/isExtensible +--- +
{{JSRef}}
+handler.isExtensible() 方法用于拦截对对象的Object.isExtensible()。
+ +
+

{{EmbedInteractiveExample("pages/js/proxyhandler-isextensible.html", "taller")}}

+
+ +

语法

+ +
var p = new Proxy(target, {
+  isExtensible: function(target) {
+  }
+});
+
+ +

参数

+ +

下列参数将会被传递给 isExtensible方法。 this 绑定在 handler 对象上。

+ +
+
target
+
目标对象。
+
+ +

返回值

+ +

isExtensible方法必须返回一个 Boolean值或可转换成Boolean的值。

+ +

描述

+ +

handler.isExtensible()用于拦截对对象的Object.isExtensible()。

+ +

拦截

+ +

该方法会拦截目标对象的以下操作:

+ + + +

约束

+ +

如果违背了以下的约束，proxy会抛出 TypeError:

+ + + +

示例

+ +

以下代码演示{{jsxref("Object.isExtensible()")}}.

+ +
var p = new Proxy({}, {
+  isExtensible: function(target) {
+    console.log('called');
+    return true;//也可以return 1;等表示为true的值
+  }
+});
+
+console.log(Object.isExtensible(p)); // "called"
+                                     // true
+
+ +

以下代码演示违反约束的情况。

+ +
var p = new Proxy({}, {
+  isExtensible: function(target) {
+    return false;//return 0;return NaN等都会报错
+  }
+});
+
+Object.isExtensible(p); // TypeError is thrown
+
+ +

规范

+ + + + + + + + + + + + + + + + + + + +
SpecificationStatusComment
{{SpecName('ES2015', '#sec-proxy-object-internal-methods-and-internal-slots-isextensible', '[[IsExtensible]]')}}{{Spec2('ES2015')}}Initial definition.
{{SpecName('ESDraft', '#sec-proxy-object-internal-methods-and-internal-slots-isextensible', '[[IsExtensible]]')}}{{Spec2('ESDraft')}}
+ +

浏览器兼容性

+ +
+ + +

{{Compat("javascript.builtins.Proxy.handler.isExtensible")}}

+
+ +

另见

+ + diff --git a/files/zh-cn/web/javascript/reference/global_objects/proxy/proxy/ownkeys/index.html b/files/zh-cn/web/javascript/reference/global_objects/proxy/proxy/ownkeys/index.html new file mode 100644 index 0000000000..956b908375 --- /dev/null +++ b/files/zh-cn/web/javascript/reference/global_objects/proxy/proxy/ownkeys/index.html @@ -0,0 +1,193 @@ +--- +title: handler.ownKeys() +slug: Web/JavaScript/Reference/Global_Objects/Proxy/handler/ownKeys +translation_of: Web/JavaScript/Reference/Global_Objects/Proxy/Proxy/ownKeys +--- +
{{JSRef}}
+ +

handler.ownKeys() 方法用于拦截 {{jsxref("Reflect.ownKeys()")}}.

+ + + +

{{EmbedInteractiveExample("pages/js/proxyhandler-ownkeys.html", "taller")}}

+ + + +

语法

+ +
var p = new Proxy(target, {
+  ownKeys: function(target) {
+  }
+});
+
+ +

参数

+ +

下面的参数被传递给ownKeys。this被绑定在handler上。

+ +
+
target
+
目标对象.
+
+ +

返回值

+ +

ownKeys 方法必须返回一个可枚举对象.

+ +

描述

+ +

handler.ownKeys() 方法用于拦截 {{jsxref("Reflect.ownKeys()")}}.

+ +

拦截

+ +

该拦截器可以拦截以下操作::

+ + + +

约束

+ +

如果违反了下面的约束，proxy将抛出错误 {{jsxref("TypeError")}}:

+ + + +

示例

+ +

下面的代码拦截 {{jsxref("Object.getOwnPropertyNames()")}}.

+ +
var p = new Proxy({}, {
+  ownKeys: function(target) {
+    console.log('called');
+    return ['a', 'b', 'c'];
+  }
+});
+
+console.log(Object.getOwnPropertyNames(p)); // "called"
+                                            // [ 'a', 'b', 'c' ]
+ +

下面的代码违反了约定

+ +
var obj = {};
+Object.defineProperty(obj, 'a', {
+  configurable: false,
+  enumerable: true,
+  value: 10 }
+);
+
+var p = new Proxy(obj, {
+  ownKeys: function(target) {
+    return [123, 12.5, true, false, undefined, null, {}, []];
+  }
+});
+
+console.log(Object.getOwnPropertyNames(p));
+
+// TypeError: proxy [[OwnPropertyKeys]] 必须返回一个数组
+// 数组元素类型只能是String或Symbol
+
+ +

标准

+ + + + + + + + + + + + + + + + + + + +
SpecificationStatusComment
{{SpecName('ES2015', '#sec-proxy-object-internal-methods-and-internal-slots-ownpropertykeys', '[[OwnPropertyKeys]]')}}{{Spec2('ES2015')}}Initial definition.
{{SpecName('ESDraft', '#sec-proxy-object-internal-methods-and-internal-slots-ownpropertykeys', '[[OwnPropertyKeys]]')}}{{Spec2('ESDraft')}}
+ +

浏览器兼容

+ +
{{CompatibilityTable}}
+ +
+ + + + + + + + + + + + + + + + + + + +
FeatureChromeFirefox (Gecko)Internet ExplorerOperaSafari
Basic support{{CompatUnknown}}{{CompatGeckoDesktop("18")}}{{CompatUnknown}}{{CompatUnknown}}{{CompatUnknown}}
+
+ +
+ + + + + + + + + + + + + + + + + + + + + +
FeatureAndroidChrome for AndroidFirefox Mobile (Gecko)IE MobileOpera MobileSafari Mobile
Basic support{{CompatUnknown}}{{CompatUnknown}}{{CompatGeckoMobile("18")}}{{CompatUnknown}}{{CompatUnknown}}{{CompatUnknown}}
+
+ +

兼容性注意事项

+ +

Firefox火狐

+ + + +

另见

+ + diff --git a/files/zh-cn/web/javascript/reference/global_objects/proxy/proxy/preventextensions/index.html b/files/zh-cn/web/javascript/reference/global_objects/proxy/proxy/preventextensions/index.html new file mode 100644 index 0000000000..dd6823c9dd --- /dev/null +++ b/files/zh-cn/web/javascript/reference/global_objects/proxy/proxy/preventextensions/index.html @@ -0,0 +1,120 @@ +--- +title: handler.preventExtensions() +slug: Web/JavaScript/Reference/Global_Objects/Proxy/handler/preventExtensions +tags: + - Proxy 代理 拦截 +translation_of: Web/JavaScript/Reference/Global_Objects/Proxy/Proxy/preventExtensions +--- +
{{JSRef}}
+ +

handler.preventExtensions() 方法用于设置对{{jsxref("Object.preventExtensions()")}}的拦截

+ +

{{EmbedInteractiveExample("pages/js/proxyhandler-preventextensions.html", "taller")}}

+ +

语法

+ +
var p = new Proxy(target, {
+  preventExtensions: function(target) {
+  }
+});
+
+ +

参数

+ +

以下参数传递给 preventExtensions 方法. 它会绑定到这个handler.

+ +
+
target
+
所要拦截的目标对象.
+
+ +

返回值

+ +

preventExtensions 方法返回一个布尔值.

+ +

描述

+ +

handler.preventExtensions() 拦截 {{jsxref("Object.preventExtensions()")}}返回一个布尔值.

+ +

拦截

+ +

这个trap可以拦截这些操作:

+ + + +

约束

+ +

如果违反了下列规则, proxy则会抛出一个 {{jsxref("TypeError")}}:

+ + + +

示例

+ +

以下代码演示了如何拦截{{jsxref("Object.preventExtensions()")}}。

+ +
var p = new Proxy({}, {
+  preventExtensions: function(target) {
+    console.log('called');
+    Object.preventExtensions(target);
+    return true;
+  }
+});
+
+console.log(Object.preventExtensions(p)); // "called"
+                                          // false
+
+ +

以下代码违反了约束.

+ +
var p = new Proxy({}, {
+  preventExtensions: function(target) {
+    return true;
+  }
+});
+
+Object.preventExtensions(p); // 抛出类型错误
+
+ +

规范

+ + + + + + + + + + + + + + + + + + + +
SpecificationStatusComment
{{SpecName('ES2015', '#sec-proxy-object-internal-methods-and-internal-slots-preventextensions', '[[PreventExtensions]]')}}{{Spec2('ES2015')}}Initial definition.
{{SpecName('ESDraft', '#sec-proxy-object-internal-methods-and-internal-slots-preventextensions', '[[PreventExtensions]]')}}{{Spec2('ESDraft')}}
+ +

浏览器兼容性

+ +
+ + +

{{Compat("javascript.builtins.Proxy.handler.preventExtensions")}}

+
+ +

参考

+ + diff --git a/files/zh-cn/web/javascript/reference/global_objects/proxy/proxy/set/index.html b/files/zh-cn/web/javascript/reference/global_objects/proxy/proxy/set/index.html new file mode 100644 index 0000000000..c66481647a --- /dev/null +++ b/files/zh-cn/web/javascript/reference/global_objects/proxy/proxy/set/index.html @@ -0,0 +1,125 @@ +--- +title: handler.set() +slug: Web/JavaScript/Reference/Global_Objects/Proxy/handler/set +tags: + - ECMAScript6 + - JavaScript + - Method + - Proxy + - Proxy拦截 +translation_of: Web/JavaScript/Reference/Global_Objects/Proxy/Proxy/set +--- +
{{JSRef}}
+ +

handler.set() 方法是设置属性值操作的捕获器。

+ +
{{EmbedInteractiveExample("pages/js/proxyhandler-set.html", "taller")}}
+ + + +

语法

+ +
const p = new Proxy(target, {
+  set: function(target, property, value, receiver) {
+  }
+});
+
+ +

参数

+ +

以下是传递给 set() 方法的参数。this 绑定在 handler 对象上。

+ +
+
target
+
目标对象。
+
property
+
将被设置的属性名或 {{jsxref("Symbol")}}。
+
value
+
新属性值。
+
receiver
+
最初被调用的对象。通常是 proxy 本身，但 handler 的 set 方法也有可能在原型链上，或以其他方式被间接地调用（因此不一定是 proxy 本身）。 +
+

比如：假设有一段代码执行 obj.name = "jen"， obj 不是一个 proxy，且自身不含 name 属性，但是它的原型链上有一个 proxy，那么，那个 proxy 的 set() 处理器会被调用，而此时，obj 会作为 receiver 参数传进来。

+
+
+
+ +

返回值

+ +

set() 方法应当返回一个布尔值。

+ + + +

描述

+ +

handler.set() 方法用于拦截设置属性值的操作。

+ +

拦截

+ +

该方法会拦截目标对象的以下操作:

+ + + +

约束

+ +

如果违背以下的约束条件，proxy 会抛出一个 {{jsxref("TypeError")}} 异常：

+ + + +

示例

+ +

以下代码演示如何捕获属性的设置操作。

+ +
var p = new Proxy({}, {
+  set: function(target, prop, value, receiver) {
+    target[prop] = value;
+    console.log('property set: ' + prop + ' = ' + value);
+    return true;
+  }
+})
+
+console.log('a' in p);  // false
+
+p.a = 10;               // "property set: a = 10"
+console.log('a' in p);  // true
+console.log(p.a);       // 10
+ +

规范

+ + + + + + + + + + + + +
规范
{{SpecName('ESDraft', '#sec-proxy-object-internal-methods-and-internal-slots-set-p-v-receiver', '[[Set]]')}}
+ +

浏览器兼容性

+ + + +

{{Compat("javascript.builtins.Proxy.handler.set")}}

+ +

另见

+ + diff --git a/files/zh-cn/web/javascript/reference/global_objects/proxy/proxy/setprototypeof/index.html b/files/zh-cn/web/javascript/reference/global_objects/proxy/proxy/setprototypeof/index.html new file mode 100644 index 0000000000..9d88cd2593 --- /dev/null +++ b/files/zh-cn/web/javascript/reference/global_objects/proxy/proxy/setprototypeof/index.html @@ -0,0 +1,124 @@ +--- +title: handler.setPrototypeOf() +slug: Web/JavaScript/Reference/Global_Objects/Proxy/handler/setPrototypeOf +translation_of: Web/JavaScript/Reference/Global_Objects/Proxy/Proxy/setPrototypeOf +--- +
{{JSRef}}
+ +

handler.setPrototypeOf() 方法主要用来拦截 {{jsxref("Object.setPrototypeOf()")}}.

+ +

语法

+ +
var p = new Proxy(target, {
+  setPrototypeOf: function(target, prototype) {
+  }
+});
+
+ +

参数

+ +

以下参数传递给 setPrototypeOf 方法. 

+ +
+
target
+
被拦截目标对象.
+
prototype
+
对象新原型或为null.
+
+ +

返回值

+ +

如果成功修改了[[Prototype]], setPrototypeOf 方法返回 true,否则返回 false.

+ +

描述

+ +

这个 handler.setPrototypeOf 方法用于拦截 {{jsxref("Object.setPrototypeOf()")}}.

+ +

拦截

+ +

这个方法可以拦截以下操作:

+ + + +

Invariants

+ +

如果违反了下列规则，则proxy将抛出一个{{jsxref("TypeError")}}:

+ + + +

示例

+ +

如果你不想为你的对象设置一个新的原型，你的handler's的setPrototypeOf方法可以返回false，也可以抛出异常。

+ +

The former approach means that any operation that performs such mutation, that throws an exception on failure to mutate, will have to create the exception itself.  For example, {{jsxref("Object.setPrototypeOf()")}} will create and throw a TypeError itself.  If the mutation is performed by an operation that doesn't ordinarily throw in case of failure, such as {{jsxref("Reflect.setPrototypeOf()")}}, no exception will be thrown.

+ +
var handlerReturnsFalse = {
+    setPrototypeOf(target, newProto) {
+        return false;
+    }
+};
+
+var newProto = {}, target = {};
+
+var p1 = new Proxy(target, handlerReturnsFalse);
+Object.setPrototypeOf(p1, newProto); // throws a TypeError
+Reflect.setPrototypeOf(p1, newProto); // returns false
+
+ +

The latter approach will cause any operation that attempts to mutate, to throw.  This approach is required if you want even non-throwing operations to throw on failure, or you want to throw a custom exception value.

+ +
var handlerThrows = {
+    setPrototypeOf(target, newProto) {
+        throw new Error('custom error');
+    }
+};
+
+var newProto = {}, target = {};
+
+var p2 = new Proxy(target, handlerThrows);
+Object.setPrototypeOf(p2, newProto); // throws new Error("custom error")
+Reflect.setPrototypeOf(p2, newProto); // throws new Error("custom error")
+ +

Specifications

+ + + + + + + + + + + + + + + + + + + +
SpecificationStatusComment
{{SpecName('ES2015', '#sec-proxy-object-internal-methods-and-internal-slots-setprototypeof-v', '[[SetPrototypeOf]]')}}{{Spec2('ES2015')}}Initial definition.
{{SpecName('ESDraft', '#sec-proxy-object-internal-methods-and-internal-slots-setprototypeof-v', '[[SetPrototypeOf]]')}}{{Spec2('ESDraft')}} 
+ +

Browser compatibility

+ +
+ + +

{{Compat("javascript.builtins.Proxy.handler.setPrototypeOf")}}

+
+ +

See also

+ + -- cgit v1.2.3-54-g00ecf