97 lines
2.3 KiB
Markdown
97 lines
2.3 KiB
Markdown
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---
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id: 56533eb9ac21ba0edf2244bf
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title: Local Scope and Functions
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challengeType: 1
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videoUrl: ''
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localeTitle: 本地范围和功能
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---
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## Description
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<section id="description">在函数内声明的变量，以及函数参数都具有<dfn>局部</dfn>范围。这意味着，它们仅在该功能中可见。这是一个函数<code>myTest</code>带有一个名为<code>loc</code>的局部变量。 <blockquote> function myTest（）{ <br> var loc =“foo”; <br>的console.log（LOC）; <br> } <br> MYTEST（）; //记录“foo” <br>的console.log（LOC）; // loc未定义</blockquote> <code>loc</code>未在函数外定义。 </section>
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## Instructions
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<section id="instructions">在<code>myLocalScope</code>声明一个局部变量<code>myVar</code> 。运行测试，然后按照编辑器中注释的说明进行操作。 <strong>暗示</strong> <br>如果您遇到问题，刷新页面可能会有所帮助。 </section>
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## Tests
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<section id='tests'>
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```yml
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tests:
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- text: 没有全局<code>myVar</code>变量
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testString: 'assert(typeof myVar === "undefined", "No global <code>myVar</code> variable");'
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- text: 添加本地<code>myVar</code>变量
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testString: 'assert(/var\s+myVar/.test(code), "Add a local <code>myVar</code> variable");'
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```
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</section>
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## Challenge Seed
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<section id='challengeSeed'>
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<div id='js-seed'>
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```js
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function myLocalScope() {
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'use strict'; // you shouldn't need to edit this line
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console.log(myVar);
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}
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myLocalScope();
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// Run and check the console
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// myVar is not defined outside of myLocalScope
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console.log(myVar);
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// Now remove the console log line to pass the test
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```
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</div>
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### Before Test
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<div id='js-setup'>
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```js
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var logOutput = "";
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var originalConsole = console
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function capture() {
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var nativeLog = console.log;
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console.log = function (message) {
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logOutput = message;
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if(nativeLog.apply) {
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nativeLog.apply(originalConsole, arguments);
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} else {
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var nativeMsg = Array.prototype.slice.apply(arguments).join(' ');
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nativeLog(nativeMsg);
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}
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};
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}
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function uncapture() {
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console.log = originalConsole.log;
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}
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```
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</div>
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### After Test
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<div id='js-teardown'>
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```js
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console.info('after the test');
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```
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</div>
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</section>
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## Solution
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<section id='solution'>
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```js
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// solution required
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```
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</section>
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