WaitSocket.js

Simplifies communication over WebSocket.

Features

• Serialization/Deserialization out of the box

• More structured way to exchange messages (separates type from payload)

  waitSocket.sendMessage('MESSAGE_TYPE', { somePayload: 'example' });

• Convenient way to handle incoming messages:

  waitSocket.on('MESSAGE_TYPE', (payload) => doSomething(payload));

• Ability to use a request/response paradigm with WebSockets (mechanism described below):

  const { payload } = await waitSocket.sendRequest('MESSAGE_TYPE', requestPayload);

• JSONSchema validation of each type of incoming and outgoing messages:

  waitSocket.validation.incoming.addJSONSchema('MESSAGE_TYPE', jsonSchemaObject);

• Ability to add interceptors to modify incoming and outgoing messages:

  waitSocket.interceptors.incoming.use((messageObject) => {
    console.log('Let\'s see what we have received', messageObject);
    // And modify the object
    return {
      ...messageObject,
      something: 'new',
    };
  });

• Flexible message format customization

• Fully TypeScript

Installation

npm i waitsocket

or

yarn add waitsocket

Usage

Importing

import WaitSocket from 'waitsocket';

Creating instance

const waitSocket = new WaitSocket('ws://my.websocket.server:9000');

Or you can use it with your own instance of WebSocket, or even with some extensions like RobustWebSocket:

const ws = new RobustWebSocket('ws://my.websocket.server:9000');
const waitSocket = new WaitSocket(ws);

JSONSchema Validation

You can define JSONSchema for each type of your incoming and outgoing messages. For incoming messages, validation process original deserialized message (before any interceptors). For outgoing messages, validation process resulting message (after all interceptors, but before serialization, of course).

waitSocket.validation.incoming.addJSONSchema('INCOMING_MESSAGE_TYPE', incomingJSONSchemaObject);
waitSocket.validation.outgoing.addJSONSchema('OUTGOING_MESSAGE_TYPE', outgoingJSONSchemaObject);

Customization

If you wish to use your own message format, you can do it by extending WaitSocket class and overriding these functions, responsible for message construction and parsing:

• getType(messageObject: MessageType): string - Returns message type.
• getPayload(messageObject: MessageType): any - Returns message payload.
• getRequestId(messageObject: MessageType): string - Returns message requestId meta data.
• getMessageObject(type: string, payload?: any, requestId?: string): MessageType; - Returns message object with type, payload and requestId in it.

Example (using body parameter instead of payload):

class myWaitSocket extends AbstractWaitSocket<MyMessageType> {
  protected getMessageObject(type: string, payload?: any, requestId?: string) {
    const result: DefaultMessageType = { type };
    if (payload) {
      result.body = payload;
    }
    if (requestId) {
      result.meta = { requestId };
    }
    return result;
  }


  public getPayload(messageObject: PlainObject) {
    return messageObject.body;
  }
}