From 33058f2b292b3a581333bdfb21b8f671898c5060 Mon Sep 17 00:00:00 2001 From: Peter Bengtsson Date: Tue, 8 Dec 2020 14:40:17 -0500 Subject: initial commit --- .../reference/global_objects/int8array/index.html | 258 +++++++++++++++++++++ 1 file changed, 258 insertions(+) create mode 100644 files/zh-cn/web/javascript/reference/global_objects/int8array/index.html (limited to 'files/zh-cn/web/javascript/reference/global_objects/int8array/index.html') diff --git a/files/zh-cn/web/javascript/reference/global_objects/int8array/index.html b/files/zh-cn/web/javascript/reference/global_objects/int8array/index.html new file mode 100644 index 0000000000..a2916916a9 --- /dev/null +++ b/files/zh-cn/web/javascript/reference/global_objects/int8array/index.html @@ -0,0 +1,258 @@ +--- +title: Int8Array +slug: Web/JavaScript/Reference/Global_Objects/Int8Array +tags: + - Int8Array + - 构造器 + - 特定类型数组 +translation_of: Web/JavaScript/Reference/Global_Objects/Int8Array +--- +
{{JSRef}}
+ +

Int8Array 类型数组表示二进制补码8位有符号整数的数组。内容初始化为0。 一旦建立，你可以使用对象的方法引用数组中的元素，或使用标准数组索引语法( 即，使用括号注释)。

+ +

语法

+ +
new Int8Array(length);
+new Int8Array(typedArray);
+new Int8Array(object);
+new Int8Array(buffer [, byteOffset [, length]]);
+ +

有关构造函数语法和参数的更多信息，请访问 TypedArray.

+ +

属性

+ +
+
{{jsxref("TypedArray.BYTES_PER_ELEMENT", "Int8Array.BYTES_PER_ELEMENT")}}
+
返回数组中每个元素的大小. 在Int8Array中这个值为1.
+
Int8Array.length
+
此属性为固定值属性，值为3.查看 {{jsxref("TypedArray.prototype.length", "Int8Array.prototype.length")}}获得获取数组内元素个数方法。
+
{{jsxref("TypedArray.name", "Int8Array.name")}}
+
返回构造器方法名称.在Int8Array类型中此值为 "Int8Array"。
+
{{jsxref("TypedArray.prototype", "Int8Array.prototype")}}
+
TypedArray 对象的构造原型。
+
+ +

方法

+ +
+
{{jsxref("TypedArray.from", "Int8Array.from()")}}
+
从类数组对象或迭代器生成int8Array数组对象. 参照{{jsxref("Array.from()")}}.
+
{{jsxref("TypedArray.of", "Int8Array.of()")}}
+
以多个参数构造Int8Array对象， 参照 {{jsxref("Array.of()")}}.
+
+ +

Int8Array 原型方法

+ +

所有 Int8Array对象都继承自 {{jsxref("TypedArray.prototype", "%TypedArray%.prototype")}}.

+ +

属性

+ +
+
Int8Array.prototype.constructor
+
这个方法会返回对象的构造原型. 默认为Int8Array构造函数.
+
{{jsxref("TypedArray.prototype.buffer", "Int8Array.prototype.buffer")}} {{readonlyInline}}
+
Returns the {{jsxref("ArrayBuffer")}} referenced by the Int8Array Fixed at construction time and thus read only.
+
{{jsxref("TypedArray.prototype.byteLength", "Int8Array.prototype.byteLength")}} {{readonlyInline}}
+
Returns the length (in bytes) of the Int8Array from the start of its {{jsxref("ArrayBuffer")}}. Fixed at construction time and thus read only.
+
{{jsxref("TypedArray.prototype.byteOffset", "Int8Array.prototype.byteOffset")}} {{readonlyInline}}
+
Returns the offset (in bytes) of the Int8Array from the start of its {{jsxref("ArrayBuffer")}}. Fixed at construction time and thus read only.
+
{{jsxref("TypedArray.prototype.length", "Int8Array.prototype.length")}} {{readonlyInline}}
+
Returns the number of elements hold in the Int8Array. Fixed at construction time and thus read only.
+
+ +

方法

+ +
+
{{jsxref("TypedArray.copyWithin", "Int8Array.prototype.copyWithin()")}}
+
Copies a sequence of array elements within the array. See also {{jsxref("Array.prototype.copyWithin()")}}.
+
{{jsxref("TypedArray.entries", "Int8Array.prototype.entries()")}}
+
Returns a new Array Iterator object that contains the key/value pairs for each index in the array. See also {{jsxref("Array.prototype.entries()")}}.
+
{{jsxref("TypedArray.every", "Int8Array.prototype.every()")}}
+
Tests whether all elements in the array pass the test provided by a function. See also {{jsxref("Array.prototype.every()")}}.
+
{{jsxref("TypedArray.fill", "Int8Array.prototype.fill()")}}
+
Fills all the elements of an array from a start index to an end index with a static value. See also {{jsxref("Array.prototype.fill()")}}.
+
{{jsxref("TypedArray.filter", "Int8Array.prototype.filter()")}}
+
Creates a new array with all of the elements of this array for which the provided filtering function returns true. See also {{jsxref("Array.prototype.filter()")}}.
+
{{jsxref("TypedArray.find", "Int8Array.prototype.find()")}}
+
Returns the found value in the array, if an element in the array satisfies the provided testing function or undefined if not found. See also {{jsxref("Array.prototype.find()")}}.
+
{{jsxref("TypedArray.findIndex", "Int8Array.prototype.findIndex()")}}
+
Returns the found index in the array, if an element in the array satisfies the provided testing function or -1 if not found. See also {{jsxref("Array.prototype.findIndex()")}}.
+
{{jsxref("TypedArray.forEach", "Int8Array.prototype.forEach()")}}
+
Calls a function for each element in the array. See also {{jsxref("Array.prototype.forEach()")}}.
+
{{jsxref("TypedArray.includes", "Int8Array.prototype.includes()")}} {{experimental_inline}}
+
Determines whether a typed array includes a certain element, returning true or false as appropriate. See also {{jsxref("Array.prototype.includes()")}}.
+
{{jsxref("TypedArray.indexOf", "Int8Array.prototype.indexOf()")}}
+
Returns the first (least) index of an element within the array equal to the specified value, or -1 if none is found. See also {{jsxref("Array.prototype.indexOf()")}}.
+
{{jsxref("TypedArray.join", "Int8Array.prototype.join()")}}
+
Joins all elements of an array into a string. See also {{jsxref("Array.prototype.join()")}}.
+
{{jsxref("TypedArray.keys", "Int8Array.prototype.keys()")}}
+
Returns a new Array Iterator that contains the keys for each index in the array. See also {{jsxref("Array.prototype.keys()")}}.
+
{{jsxref("TypedArray.lastIndexOf", "Int8Array.prototype.lastIndexOf()")}}
+
Returns the last (greatest) index of an element within the array equal to the specified value, or -1 if none is found. See also {{jsxref("Array.prototype.lastIndexOf()")}}.
+
{{jsxref("TypedArray.map", "Int8Array.prototype.map()")}}
+
返回一个由回调函数的返回值组成的新数组。. See also {{jsxref("Array.prototype.map()")}}.
+
{{jsxref("TypedArray.move", "Int8Array.prototype.move()")}} {{non-standard_inline}} {{unimplemented_inline}}
+
{{jsxref("TypedArray.copyWithin", "Int8Array.prototype.copyWithin()")}} 早期的不标准定义。
+
{{jsxref("TypedArray.reduce", "Int8Array.prototype.reduce()")}}
+
从左到右为每个数组元素执行一次回调函数，并把上次回调函数的返回值放在一个暂存器中传给下次回调函数，并返回最后一次回调函数的返回值。参照 {{jsxref("Array.prototype.reduce()")}}.
+
{{jsxref("TypedArray.reduceRight", "Int8Array.prototype.reduceRight()")}}
+
从右到左为每个数组元素执行一次回调函数，并把上次回调函数的返回值放在一个暂存器中传给下次回调函数，并返回最后一次回调函数的返回值。参照 {{jsxref("Array.prototype.reduceRight()")}}.
+
{{jsxref("TypedArray.reverse", "Int8Array.prototype.reverse()")}}
+
颠倒数组中元素的排列顺序，即原先的第一个变为最后一个，原先的最后一个变为第一个。参照{{jsxref("Array.prototype.reverse()")}}.
+
{{jsxref("TypedArray.set", "Int8Array.prototype.set()")}}
+
Stores multiple values in the typed array, reading input values from a specified array.
+
{{jsxref("TypedArray.slice", "Int8Array.prototype.slice()")}}
+
抽取当前数组中的一段元素组合成一个新数组。参照{{jsxref("Array.prototype.slice()")}}.
+
{{jsxref("TypedArray.some", "Int8Array.prototype.some()")}}
+
如果数组中至少有一个元素满足测试函数，则返回 true，否则返回 false。参照 {{jsxref("Array.prototype.some()")}}.
+
{{jsxref("TypedArray.sort", "Int8Array.prototype.sort()")}}
+
对数组元素进行排序，并返回当前数组. 参照{{jsxref("Array.prototype.sort()")}}.
+
{{jsxref("TypedArray.subarray", "Int8Array.prototype.subarray()")}}
+
返回一个以给定的初始结束位置裁剪的Int8Array数组.
+
{{jsxref("TypedArray.values", "Int8Array.prototype.values()")}}
+
返回一个数组迭代器对象，该迭代器会包含所有数组元素的值。. 参照 {{jsxref("Array.prototype.values()")}}.
+
{{jsxref("TypedArray.toLocaleString", "Int8Array.prototype.toLocaleString()")}}
+
返回一个由所有数组元素组合而成的本地化后的字符串. See also {{jsxref("Array.prototype.toLocaleString()")}}.
+
{{jsxref("TypedArray.toString", "Int8Array.prototype.toString()")}}
+
返回一个由所有数组元素组合而成的字符串.参照 {{jsxref("Array.prototype.toString()")}}.
+
{{jsxref("TypedArray.@@iterator", "Int8Array.prototype[@@iterator]()")}}
+
此方法返回一个带有数组内所有元素的迭代器对象，同Int8Array.prototype.values 。
+
+ +

示例

+ +
// 以长度参数构造对象
+var int8 = new Int8Array(2);
+int8[0] = 42;
+console.log(int8[0]); // 42
+console.log(int8.length); // 2
+console.log(int8.BYTES_PER_ELEMENT); // 1
+
+// 以数组构造对象
+var arr = new Int8Array([21,31]);
+console.log(arr[1]); // 31
+
+// 从另一数组构造对象
+var x = new Int8Array([21, 31]);
+var y = new Int8Array(x);
+console.log(y[0]); // 21
+
+// 从ArrayBuffer构造对象
+var buffer = new ArrayBuffer(8);
+var z = new Int8Array(buffer, 1, 4);
+
+ +

规范

+ + + + + + + + + + + + + + + + + + + + + + + + +
规范状态评论
{{SpecName('Typed Array')}}{{Spec2('Typed Array')}}已被 ECMAScript 6取代。
{{SpecName('ES6', '#table-49', 'TypedArray constructors')}}{{Spec2('ES6')}}ECMA 标准中构造对象时 new 关键字为必需。
{{SpecName('ESDraft', '#table-49', 'TypedArray constructors')}}{{Spec2('ESDraft')}} 
+ +

浏览器兼容性

+ +

{{CompatibilityTable}}

+ +
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功能ChromeFirefox (Gecko)Internet ExplorerOperaSafari
Basic support7.0{{ CompatGeckoDesktop("2") }}1011.65.1
new is required{{CompatUnknown}}{{ CompatGeckoDesktop("44") }}{{CompatUnknown}}{{CompatUnknown}}{{CompatUnknown}}
+
+ +
+ + + + + + + + + + + + + + + + + + + + + + + + + + + + + + +
FeatureAndroidChrome for AndroidFirefox Mobile (Gecko)IE MobileOpera MobileSafari Mobile
Basic support4.0{{CompatVersionUnknown}}{{ CompatGeckoMobile("2") }}1011.64.2
new is required{{CompatUnknown}}{{CompatUnknown}}{{ CompatGeckoMobile("44") }}{{CompatUnknown}}{{CompatUnknown}}{{CompatUnknown}}
+
+ +

兼容性说明

+ +

自 ECMAScript 2015 (ES6)施行, Int8Array 需要使用{{jsxref("Operators/new", "new")}} 构造. 从当前版本开始，不加new而便调用Int8Array 构造器方法, 将报出 {{jsxref("TypeError")}} 错误.

+ +
var dv = Int8Array([1, 2, 3]);
+// TypeError: calling a builtin Int8Array constructor
+// without new is forbidden
+ +
var dv = new Int8Array([1, 2, 3]);
+ +

相关链接

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