5bf8527523
* fix: rm assert msg basic-algorithm-scripting * fix: rm assert msg debugging * fix: rm assert msg es6 * fix: rm assert msg functional-programming
90 lines
2.1 KiB
Markdown
90 lines
2.1 KiB
Markdown
---
|
|
id: 587d7b88367417b2b2512b44
|
|
title: Write Arrow Functions with Parameters
|
|
challengeType: 1
|
|
---
|
|
|
|
## Description
|
|
<section id='description'>
|
|
Just like a regular function, you can pass arguments into an arrow function.
|
|
|
|
```js
|
|
// doubles input value and returns it
|
|
const doubler = (item) => item * 2;
|
|
```
|
|
|
|
If an arrow function has a single argument, the parentheses enclosing the argument may be omitted.
|
|
|
|
```js
|
|
// the same function, without the argument parentheses
|
|
const doubler = item => item * 2;
|
|
```
|
|
|
|
It is possible to pass more than one argument into an arrow function.
|
|
|
|
```js
|
|
// multiplies the first input value by the second and returns it
|
|
const multiplier = (item, multi) => item * multi;
|
|
```
|
|
|
|
</section>
|
|
|
|
## Instructions
|
|
<section id='instructions'>
|
|
Rewrite the <code>myConcat</code> function which appends contents of <code>arr2</code> to <code>arr1</code> so that the function uses arrow function syntax.
|
|
</section>
|
|
|
|
## Tests
|
|
<section id='tests'>
|
|
|
|
```yml
|
|
tests:
|
|
- text: User did replace <code>var</code> keyword.
|
|
testString: getUserInput => assert(!getUserInput('index').match(/var/g));
|
|
- text: <code>myConcat</code> should be a constant variable (by using <code>const</code>).
|
|
testString: getUserInput => assert(getUserInput('index').match(/const\s+myConcat/g));
|
|
- text: <code>myConcat</code> should be a function
|
|
testString: assert(typeof myConcat === 'function');
|
|
- text: <code>myConcat()</code> returns the correct <code>array</code>
|
|
testString: assert(() => { const a = myConcat([1], [2]); return a[0] == 1 && a[1] == 2; });
|
|
- text: <code>function</code> keyword was not used.
|
|
testString: getUserInput => assert(!getUserInput('index').match(/function/g));
|
|
|
|
```
|
|
|
|
</section>
|
|
|
|
## Challenge Seed
|
|
<section id='challengeSeed'>
|
|
|
|
<div id='js-seed'>
|
|
|
|
```js
|
|
var myConcat = function(arr1, arr2) {
|
|
"use strict";
|
|
return arr1.concat(arr2);
|
|
};
|
|
// test your code
|
|
console.log(myConcat([1, 2], [3, 4, 5]));
|
|
```
|
|
|
|
</div>
|
|
|
|
|
|
|
|
</section>
|
|
|
|
## Solution
|
|
<section id='solution'>
|
|
|
|
```js
|
|
const myConcat = (arr1, arr2) => {
|
|
"use strict";
|
|
return arr1.concat(arr2);
|
|
};
|
|
// test your code
|
|
console.log(myConcat([1, 2], [3, 4, 5]));
|
|
```
|
|
|
|
</section>
|