5-kyu-extract-the-domain-name-from-a-url.js

// 5 kyu | Extract the domain name from a URL
// https://www.codewars.com/kata/514a024011ea4fb54200004b

/*

Write a function that when given a URL as a string, parses out just the domain
name and returns it as a string. For example:

```
domainName("http://github.com/carbonfive/raygun") == "github"
domainName("http://www.zombie-bites.com") == "zombie-bites"
domainName("https://www.cnet.com") == "cnet"
```

*/

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const domainName = url => url.match(/^(?:[^\/]*\/\/)?(?:www\.)?([^.]+)\./)[1];

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import { strictEqual } from 'assert';

strictEqual(domainName('http://google.com'), 'google');
strictEqual(domainName('http://google.co.jp'), 'google');
strictEqual(domainName('www.xakep.ru'), 'xakep');
strictEqual(domainName('https://youtube.com'), 'youtube');