64 lines
2.0 KiB
Markdown
64 lines
2.0 KiB
Markdown
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---
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id: 587d7b88367417b2b2512b46
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title: Set Default Parameters for Your Functions
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challengeType: 1
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---
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## Description
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<section id='description'>
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In order to help us create more flexible functions, ES6 introduces <dfn>default parameters</dfn> for functions.
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Check out this code:
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<blockquote>function greeting(name = "Anonymous") {<br> return "Hello " + name;<br>}<br>console.log(greeting("John")); // Hello John<br>console.log(greeting()); // Hello Anonymous</blockquote>
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The default parameter kicks in when the argument is not specified (it is undefined). As you can see in the example above, the parameter <code>name</code> will receive its default value <code>"Anonymous"</code> when you do not provide a value for the parameter. You can add default values for as many parameters as you want.
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</section>
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## Instructions
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<section id='instructions'>
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Modify the function <code>increment</code> by adding default parameters so that it will add 1 to <code>number</code> if <code>value</code> is not specified.
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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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- text: 'The result of <code>increment(5, 2)</code> should be <code>7</code>.'
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testString: 'assert(increment(5, 2) === 7, "The result of <code>increment(5, 2)</code> should be <code>7</code>.");'
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- text: The result of <code>increment(5)</code> should be <code>6</code>.
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testString: 'assert(increment(5) === 6, "The result of <code>increment(5)</code> should be <code>6</code>.");'
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- text: default parameter <code>1</code> was used for <code>value</code>.
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testString: 'getUserInput => assert(getUserInput("index").match(/value\s*=\s*1/g), "default parameter <code>1</code> was used for <code>value</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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const increment = (function() {
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"use strict";
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return function increment(number, value) {
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return number + value;
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};
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})();
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console.log(increment(5, 2)); // returns 7
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console.log(increment(5)); // returns 6
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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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