# Extract domain name from URL

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This package provides a performant way to extract domain names from URLs without using regular expressions or array manipulations.

Learn more about [What is a URL](https://developer.mozilla.org/en-US/docs/Learn/Common_questions/What_is_a_URL)

## Supports

-   ESM
-   Node.js
-   Browser

## Usage

### Installation

```bash
$ npm i --save extract-domain
```

### Development

```
# Install bun https://bun.sh/
curl -fsSL https://bun.sh/install | bash


# tests
bun test:watch
```

### API

-   @param {Urls} urls ["https://www.google.com", "https://www.github.com"] or "https://www.google.com"
-   @param {GetDomainOptions} opts `{ tld: true }` permit to get Top Level Domain like `*.co.uk`
-   @returns {Urls | Promise<Urls>} Returns URL(s) or a promise of URL(s) if the PSL lib is being used

ESM import

```js
import extractDomain from 'extract-domain';
```

Examples

```js
const urls = [
    'https://www.npmjs.com/package/extract-domain',
    'http://www.example.com:80/path/to/myfile.html?key1=value1&key2=value2#SomewhereInTheDocument',
    'http://user:password@example.com:80/path/to/myfile.html?key1=value1&key2=value2#SomewhereInTheDocument',
    'https://npmjs.com/package/extract-domain',
    'ftp://example.org/resource.txt',
    'http://example.co.uk/',
    'this.is.my@email.com',
];

extractDomain(urls[0]); // npmjs.com

extractDomain(urls); // [ 'npmjs.com', 'example.com', 'example.com', 'npmjs.com', 'example.org', 'co.uk', 'email.com' ]
```

## TLD support

TLD support requires the optional dependency of the [`psl` library](https://www.npmjs.com/package/psl).

Examples

```bash
npm i --save-optional psl
```

```js
const url =
    'http://www.example.co.uk:80/path/to/myfile.html?key1=value1&key2=value2#SomewhereInTheDocument';

async function extract(url) {
    console.log(await extractDomain(url, { tld: true }));
    // example.co.uk
}

// Or
extractDomain(url, { tld: true }).then(console.log);
// example.co.uk
```

Please note that using the tld flag may significantly slow down the process. Benchmark (old) results:

```
# extract domain 10,000 times
  end ~14 ms (0 s + 13572914 ns)
# extract domain with tld 10,000 times
  end ~4.29 s (4 s + 288108681 ns)
```

## Tests

```bash
$ bun test
```

## Coding style

```bash
$ bun pretty
```

## Benchmark

```bash
$ bun benchmark
```

## Contribution

Contributions are appreciated.

## License

MIT-licensed. See LICENSE.