3ec1fe8ea7
This commit adds the pre-existing challenge guide topics in the forum to the forntmatter of their challenge markdown files.
124 lines
2.4 KiB
Markdown
124 lines
2.4 KiB
Markdown
---
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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: 'https://scrimba.com/c/cd62NhM'
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forumTopicId: 18227
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---
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## Description
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<section id='description'>
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Variables which are declared within a function, as well as the function parameters have <dfn>local</dfn> scope. That means, they are only visible within that function.
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Here is a function <code>myTest</code> with a local variable called <code>loc</code>.
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```js
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function myTest() {
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var loc = "foo";
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console.log(loc);
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}
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myTest(); // logs "foo"
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console.log(loc); // loc is not defined
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```
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<code>loc</code> is not defined outside of the function.
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</section>
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## Instructions
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<section id='instructions'>
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Declare a local variable <code>myVar</code> inside <code>myLocalScope</code>. Run the tests and then follow the instructions commented out in the editor.
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<strong>Hint</strong><br>Refreshing the page may help if you get stuck.
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</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: No global <code>myVar</code> variable
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testString: assert(typeof myVar === 'undefined');
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- text: Add a local <code>myVar</code> variable
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testString: assert(/function\s+myLocalScope\s*\(\s*\)\s*\{\s[\s\S]+\s*var\s*myVar\s*(\s*|=[\s\S]+)\s*;[\s\S]+}/.test(code));
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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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typeof myLocalScope === 'function' && (capture(), myLocalScope(), uncapture());
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(function() { return logOutput || "console.log never called"; })();
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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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function myLocalScope() {
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'use strict';
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var myVar;
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console.log(myVar);
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}
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myLocalScope();
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```
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</section>
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