79d9012432
* fix(curriculum): tests quotes * fix(curriculum): fill seed-teardown * fix(curriculum): fix tests and remove unneeded seed-teardown
112 lines
2.4 KiB
Markdown
112 lines
2.4 KiB
Markdown
---
|
|
id: 56533eb9ac21ba0edf2244bf
|
|
title: Local Scope and Functions
|
|
challengeType: 1
|
|
---
|
|
|
|
## Description
|
|
<section id='description'>
|
|
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.
|
|
Here is a function <code>myTest</code> with a local variable called <code>loc</code>.
|
|
<blockquote>function myTest() {<br> var loc = "foo";<br> console.log(loc);<br>}<br>myTest(); // logs "foo"<br>console.log(loc); // loc is not defined</blockquote>
|
|
<code>loc</code> is not defined outside of the function.
|
|
</section>
|
|
|
|
## Instructions
|
|
<section id='instructions'>
|
|
Declare a local variable <code>myVar</code> inside <code>myLocalScope</code>. Run the tests and then follow the instructions commented out in the editor.
|
|
<strong>Hint</strong><br>Refreshing the page may help if you get stuck.
|
|
</section>
|
|
|
|
## Tests
|
|
<section id='tests'>
|
|
|
|
```yml
|
|
tests:
|
|
- text: No global <code>myVar</code> variable
|
|
testString: assert(typeof myVar === 'undefined', 'No global <code>myVar</code> variable');
|
|
- text: Add a local <code>myVar</code> variable
|
|
testString: assert(/var\s+myVar/.test(code), 'Add a local <code>myVar</code> variable');
|
|
|
|
```
|
|
|
|
</section>
|
|
|
|
## Challenge Seed
|
|
<section id='challengeSeed'>
|
|
|
|
<div id='js-seed'>
|
|
|
|
```js
|
|
function myLocalScope() {
|
|
'use strict'; // you shouldn't need to edit this line
|
|
|
|
console.log(myVar);
|
|
}
|
|
myLocalScope();
|
|
|
|
// Run and check the console
|
|
// myVar is not defined outside of myLocalScope
|
|
console.log(myVar);
|
|
|
|
// Now remove the console log line to pass the test
|
|
|
|
```
|
|
|
|
</div>
|
|
|
|
### Before Test
|
|
<div id='js-setup'>
|
|
|
|
```js
|
|
var logOutput = "";
|
|
var originalConsole = console
|
|
function capture() {
|
|
var nativeLog = console.log;
|
|
console.log = function (message) {
|
|
logOutput = message;
|
|
if(nativeLog.apply) {
|
|
nativeLog.apply(originalConsole, arguments);
|
|
} else {
|
|
var nativeMsg = Array.prototype.slice.apply(arguments).join(' ');
|
|
nativeLog(nativeMsg);
|
|
}
|
|
};
|
|
}
|
|
|
|
function uncapture() {
|
|
console.log = originalConsole.log;
|
|
}
|
|
|
|
```
|
|
|
|
</div>
|
|
|
|
### After Test
|
|
<div id='js-teardown'>
|
|
|
|
```js
|
|
typeof myLocalScope === 'function' && (capture(), myLocalScope(), uncapture());
|
|
(function() { return logOutput || "console.log never called"; })();
|
|
```
|
|
|
|
</div>
|
|
|
|
</section>
|
|
|
|
## Solution
|
|
<section id='solution'>
|
|
|
|
|
|
```js
|
|
function myLocalScope() {
|
|
'use strict';
|
|
|
|
var myVar;
|
|
console.log(myVar);
|
|
}
|
|
myLocalScope();
|
|
```
|
|
|
|
</section>
|