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https://github.com/thoov/mock-socket

Javascript mocking library for WebSockets and Socket.IO
https://github.com/thoov/mock-socket

javascript mocking testing websockets

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Javascript mocking library for WebSockets and Socket.IO

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README 

        


  






Javascript mocking library for websockets and socket.io






  

    Build Status

  




## Contents



- [Installation](#installation)

- [Basic Usage](#usage)

- [Advanced Usage](#advanced-usage)

- [Typescript Support](#typescript-support)

- [Socket.IO](#socket-io)

- [Contributing](#contributing)

- [Feedback](#feedback)



## Installation



```shell

npm install mock-socket

```



```js

import { WebSocket, Server } from 'mock-socket';

```



## Usage



```js

import test from 'ava';

import { Server } from 'mock-socket';



class ChatApp {

  constructor(url) {

    this.messages = [];

    this.connection = new WebSocket(url);



    this.connection.onmessage = event => {

      this.messages.push(event.data);

    };

  }



  sendMessage(message) {

    this.connection.send(message);

  }

}



test.cb('that chat app can be mocked', t => {

  const fakeURL = 'ws://localhost:8080';

  const mockServer = new Server(fakeURL);



  mockServer.on('connection', socket => {

    socket.on('message', data => {

      t.is(data, 'test message from app', 'we have intercepted the message and can assert on it');

      socket.send('test message from mock server');

    });

  });



  const app = new ChatApp(fakeURL);

  app.sendMessage('test message from app'); // NOTE: this line creates a micro task



  // NOTE: this timeout is for creating another micro task that will happen after the above one

  setTimeout(() => {

    t.is(app.messages.length, 1);

    t.is(app.messages[0], 'test message from mock server', 'we have stubbed our websocket backend');

    mockServer.stop(t.done);

  }, 100);

});

```



## Advanced Usage



### Stubbing the "global"



```js

import { WebSocket, Server } from 'mock-socket';



/*

 * By default the global WebSocket object is stubbed out when 

 * a new Server instance is created and is restored when you stop

 * the server.

 * However, you can disable this behavior by passing `mock: false`

 * to the options and manually mock the socket when you need it.

 */

const server = new Server('ws://localhost:8080', { mock: false });



/*

 * If you need to stub something else out you can like so:

 */



window.WebSocket = WebSocket; // Here we stub out the window object

```



### Server Methods



```js

const mockServer = new Server('ws://localhost:8080');



mockServer.on('connection', socket => {

  socket.on('message', () => {});

  socket.on('close', () => {});

  socket.on('error', () => {});



  socket.send('message');

  socket.close();

});



mockServer.clients(); // array of all connected clients

mockServer.emit('room', 'message');

mockServer.stop(optionalCallback);

```



## Typescript Support



A [declaration file](https://github.com/thoov/mock-socket/blob/master/index.d.ts) is included by default. If you notice any issues with the types please create an issue or a PR!



## Socket IO



[Socket.IO](https://socket.io/) has **limited support**. Below is a similar example to the one above but modified to show off socket.io support.



```js

import test from 'ava';

import { SocketIO, Server } from 'mock-socket';



class ChatApp {

  constructor(url) {

    this.messages = [];

    this.connection = new io(url);



    this.connection.on('chat-message', data => {

      this.messages.push(event.data);

    });

  }



  sendMessage(message) {

    this.connection.emit('chat-message', message);

  }

}



test.cb('that socket.io works', t => {

  const fakeURL = 'ws://localhost:8080';

  const mockServer = new Server(fakeURL);



  window.io = SocketIO;



  mockServer.on('connection', socket => {

    socket.on('chat-message', data => {

      t.is(data, 'test message from app', 'we have intercepted the message and can assert on it');

      socket.emit('chat-message', 'test message from mock server');

    });

  });



  const app = new ChatApp(fakeURL);

  app.sendMessage('test message from app');



  setTimeout(() => {

    t.is(app.messages.length, 1);

    t.is(app.messages[0], 'test message from mock server', 'we have subbed our websocket backend');



    mockServer.stop(t.done);

  }, 100);

});

```



## Contributing



The easiest way to work on the project is to clone the repo down via:



```shell

git clone [email protected]:thoov/mock-socket.git

cd mock-socket

yarn install

```



Then to create a local build via:



```shell

yarn build

```



Then create a local npm link via:



```shell

yarn link

```



At this point you can create other projects / apps locally and reference this local build via:



```shell

yarn link mock-socket

```



from within your other projects folder. Make sure that after any changes you run `yarn build`!



### Tests



This project uses [ava.js](https://github.com/avajs/ava) as its test framework. Tests are located in /tests. To run tests:



```shell

yarn test

```



### Linting



This project uses eslint and a rules set from [airbnb's javascript style guides](https://github.com/airbnb/javascript). To run linting:



```shell

yarn lint

```



### Formatting



This project uses [prettier](https://github.com/prettier/prettier). To run the formatting:



```shell

yarn format

```



### Code Coverage



Code coverage reports are created in /coverage after all of the tests have successfully passed. To run the coverage:



```shell

yarn test:coverage

```



## Feedback



If you have any feedback, encounter any bugs, or just have a question, please feel free to create a [github issue](https://github.com/thoov/mock-socket/issues/new) or send me a tweet at [@thoov](https://twitter.com/thoov).