https://github.com/sindresorhus/is-online

Check if the internet connection is up
https://github.com/sindresorhus/is-online

browser connectivity detect internet internet-connection javascript network nodejs online ping reachability

Last synced: 4 days ago
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Check if the internet connection is up

• Host: GitHub
• URL: https://github.com/sindresorhus/is-online
• Owner: sindresorhus
• License: mit
• Created: 2014-09-19T17:58:49.000Z (over 10 years ago)
• Default Branch: main
• Last Pushed: 2024-07-26T15:37:48.000Z (6 months ago)
• Last Synced: 2024-10-29T15:34:45.695Z (2 months ago)
• Topics: browser, connectivity, detect, internet, internet-connection, javascript, network, nodejs, online, ping, reachability
• Language: JavaScript
• Homepage:
• Size: 88.9 KB
• Stars: 1,239
• Watchers: 25
• Forks: 83
• Open Issues: 4
• Metadata Files:
  • Readme: readme.md
  • License: license
  • Security: .github/security.md

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README

        
# is-online

> Check if the internet connection is up

Works in Node.js and the browser *(with a bundler)*.

In the browser, there is already [`navigator.onLine`](https://developer.mozilla.org/en-US/docs/Web/API/NavigatorOnLine.onLine), but it's useless as it only tells you if there's a local connection, and not whether the internet is accessible.

## Install

```sh

npm install is-online

```

## Usage

```js

import isOnline from 'is-online';

console.log(await isOnline());

//=> true

```

## API

### isOnline(options?)

#### options

Type: `object`

##### timeout

Type: `number`\

Default: `5000`

Milliseconds to wait for a server to respond.

##### ipVersion

Type: `number`\

Values: `4 | 6`\

Default: `4`

The [Internet Protocol version](https://en.wikipedia.org/wiki/Internet_Protocol#Version_history) to use.

This is an advanced option that is usually not necessary to be set, but it can prove useful to specifically assert IPv6 connectivity.

## How it works

The following checks are run in parallel:

- Retrieve [icanhazip.com](https://github.com/major/icanhaz) (or [ipify.org](https://www.ipify.org) as fallback) via HTTPS.

- Query `myip.opendns.com` and `o-o.myaddr.l.google.com` DNS entries. *(Node.js only)*

- Retrieve Apple's Captive Portal test page (this is what iOS does). *(Node.js only)*

When any check succeeds, the returned Promise is resolved to `true`.

## Proxy support

To make it work through proxies, you need to set up [`global-agent`](https://github.com/gajus/global-agent).

## Maintainers

- [Sindre Sorhus](https://github.com/sindresorhus)

- [silverwind](https://github.com/silverwind)

## Related

- [is-online-cli](https://github.com/sindresorhus/is-online-cli) - CLI for this module

- [is-reachable](https://github.com/sindresorhus/is-reachable) - Check if servers are reachable