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Diffstat (limited to 'files/zh-tw/web/javascript/reference/functions/arguments/index.html')
| -rw-r--r-- | files/zh-tw/web/javascript/reference/functions/arguments/index.html | 36 |
1 files changed, 18 insertions, 18 deletions
diff --git a/files/zh-tw/web/javascript/reference/functions/arguments/index.html b/files/zh-tw/web/javascript/reference/functions/arguments/index.html index 6b1d6a45a1..ddccefae10 100644 --- a/files/zh-tw/web/javascript/reference/functions/arguments/index.html +++ b/files/zh-tw/web/javascript/reference/functions/arguments/index.html @@ -16,7 +16,7 @@ translation_of: Web/JavaScript/Reference/Functions/arguments <h2 id="語法">語法</h2> -<pre class="syntaxbox notranslate">arguments</pre> +<pre class="syntaxbox">arguments</pre> <h2 id="描述">描述</h2> @@ -32,20 +32,20 @@ translation_of: Web/JavaScript/Reference/Functions/arguments <p>For example, if a function is passed three arguments, you can refer to them as follows:</p> -<pre class="brush: js notranslate">arguments[0] +<pre class="brush: js">arguments[0] arguments[1] arguments[2] </pre> <p>arguments 也可以被指定：</p> -<pre class="brush: js notranslate">arguments[1] = 'new value';</pre> +<pre class="brush: js">arguments[1] = 'new value';</pre> <p><code>arguments</code> 物件不是陣列。它與陣列非常相似，但是它沒有除了 <code>length</code> 這個屬性以外的其他陣列屬性。舉例，它沒有 <code>pop</code> 這個陣列方法。</p> <p>然而，它依然可以被轉換為真正的陣列(Array)。</p> -<pre class="brush: js notranslate">var args = Array.prototype.slice.call(arguments); +<pre class="brush: js">var args = Array.prototype.slice.call(arguments); var args = [].slice.call(arguments); // ES2015 @@ -55,7 +55,7 @@ const args = Array.from(arguments); <div class="warning"> <p class="brush: js">Using slice on arguments prevents optimizations in some JavaScript engines (V8 for example - <a href="https://github.com/petkaantonov/bluebird/wiki/Optimization-killers#3-managing-arguments">more information</a>). If you care for them, try constructing a new array by iterating through the arguments object instead. An alternative would be to use the despised <code>Array</code> constructor as a function:</p> -<pre class="brush: js notranslate">var args = (arguments.length === 1 ? [arguments[0]] : Array.apply(null, arguments));</pre> +<pre class="brush: js">var args = (arguments.length === 1 ? [arguments[0]] : Array.apply(null, arguments));</pre> </div> <p>You can use the <code>arguments</code> object if you call a function with more arguments than it is formally declared to accept. This technique is useful for functions that can be passed a variable number of arguments. Use <code><a href="/en-US/docs/JavaScript/Reference/Functions_and_function_scope/arguments/length">arguments.length</a></code> to determine the number of arguments passed to the function, and then process each argument by using the <code>arguments</code> object. To determine the number of parameters in the function <a href="/en-US/docs/Glossary/Signature/Function">signature</a>, use the <code><a href="/en-US/docs/JavaScript/Reference/Global_Objects/Function/length">Function.length</a></code> property.</p> @@ -64,17 +64,17 @@ const args = Array.from(arguments); <p>The typeof arguments returns 'object'. </p> -<pre class="notranslate">console.log(typeof arguments); // 'object' </pre> +<pre>console.log(typeof arguments); // 'object' </pre> <p>The typeof individual arguments can be determined with the use of indexing.</p> -<pre class="notranslate">console.log(typeof arguments[0]); //this will return the typeof individual arguments.</pre> +<pre>console.log(typeof arguments[0]); //this will return the typeof individual arguments.</pre> <h3 id="Using_the_Spread_Syntax_with_Arguments">Using the Spread Syntax with Arguments</h3> <p>You can also use the {{jsxref("Array.from()")}} method or the <a href="/en-US/docs/Web/JavaScript/Reference/Operators/Spread_operator">spread operator</a> to convert arguments to a real Array:</p> -<pre class="brush: js notranslate">var args = Array.from(arguments); +<pre class="brush: js">var args = Array.from(arguments); var args = [...arguments]; </pre> @@ -97,14 +97,14 @@ var args = [...arguments]; <p>This example defines a function that concatenates several strings. The only formal argument for the function is a string that specifies the characters that separate the items to concatenate. The function is defined as follows:</p> -<pre class="brush:js notranslate">function myConcat(separator) { +<pre class="brush:js">function myConcat(separator) { var args = Array.prototype.slice.call(arguments, 1); return args.join(separator); }</pre> <p>You can pass any number of arguments to this function, and it creates a list using each argument as an item in the list.</p> -<pre class="brush:js notranslate">// returns "red, orange, blue" +<pre class="brush:js">// returns "red, orange, blue" myConcat(', ', 'red', 'orange', 'blue'); // returns "elephant; giraffe; lion; cheetah" @@ -117,7 +117,7 @@ myConcat('. ', 'sage', 'basil', 'oregano', 'pepper', 'parsley');</pre> <p>This example defines a function that creates a string containing HTML for a list. The only formal argument for the function is a string that is "<code>u</code>" if the list is to be unordered (bulleted), or "<code>o</code>" if the list is to be ordered (numbered). The function is defined as follows:</p> -<pre class="brush:js notranslate">function list(type) { +<pre class="brush:js">function list(type) { var result = '<' + type + 'l><li>'; var args = Array.prototype.slice.call(arguments, 1); result += args.join('</li><li>'); @@ -128,7 +128,7 @@ myConcat('. ', 'sage', 'basil', 'oregano', 'pepper', 'parsley');</pre> <p>You can pass any number of arguments to this function, and it adds each argument as an item to a list of the type indicated. For example:</p> -<pre class="brush:js notranslate">var listHTML = list('u', 'One', 'Two', 'Three'); +<pre class="brush:js">var listHTML = list('u', 'One', 'Two', 'Three'); /* listHTML is: @@ -140,7 +140,7 @@ myConcat('. ', 'sage', 'basil', 'oregano', 'pepper', 'parsley');</pre> <p>The <code>arguments</code> object can be used in conjunction with <a href="/en-US/docs/Web/JavaScript/Reference/Functions/rest_parameters">rest</a>, <a href="/en-US/docs/Web/JavaScript/Reference/Functions/Default_parameters">default</a>, and <a href="/en-US/docs/Web/JavaScript/Reference/Operators/Destructuring_assignment">destructured</a> parameters.</p> -<pre class="brush: js notranslate">function foo(...args) { +<pre class="brush: js">function foo(...args) { return args; } foo(1, 2, 3); // [1,2,3] @@ -150,7 +150,7 @@ foo(1, 2, 3); // [1,2,3] <p>When a non-strict function <strong><strong>does </strong>not</strong> contain <a href="/en-US/docs/Web/JavaScript/Reference/Functions/rest_parameters">rest</a>, <a href="/en-US/docs/Web/JavaScript/Reference/Functions/Default_parameters">default</a>, or <a href="/en-US/docs/Web/JavaScript/Reference/Operators/Destructuring_assignment">destructured</a> parameters, then the values in the <code>arguments</code> object <strong>do</strong> track the values of the arguments (and vice versa). See the code below:</p> -<pre class="brush: js notranslate">function func(a) { +<pre class="brush: js">function func(a) { arguments[0] = 99; // updating arguments[0] also updates a console.log(a); } @@ -159,7 +159,7 @@ func(10); // 99 <p>and</p> -<pre class="brush: js notranslate">function func(a) { +<pre class="brush: js">function func(a) { a = 99; // updating a also updates arguments[0] console.log(arguments[0]); } @@ -168,7 +168,7 @@ func(10); // 99 <p>When a non-strict function <strong>does</strong> contain <a href="/en-US/docs/Web/JavaScript/Reference/Functions/rest_parameters">rest</a>, <a href="/en-US/docs/Web/JavaScript/Reference/Functions/Default_parameters">default</a>, or <a href="/en-US/docs/Web/JavaScript/Reference/Operators/Destructuring_assignment">destructured</a> parameters, then the values in the <code>arguments</code> object <strong>do not</strong> track the values of the arguments (and vice versa). Instead, they reflect the arguments provided at the time of invocation:</p> -<pre class="brush: js notranslate">function func(a = 55) { +<pre class="brush: js">function func(a = 55) { arguments[0] = 99; // updating arguments[0] does not also update a console.log(a); } @@ -176,7 +176,7 @@ func(10); // 10</pre> <p>and</p> -<pre class="brush: js notranslate">function func(a = 55) { +<pre class="brush: js">function func(a = 55) { a = 99; // updating a does not also update arguments[0] console.log(arguments[0]); } @@ -185,7 +185,7 @@ func(10); // 10 <p>and</p> -<pre class="brush: js notranslate">function func(a = 55) { +<pre class="brush: js">function func(a = 55) { console.log(arguments[0]); } func(); // undefined</pre> |