@design.estate/dees-comms/ts/dees-comms.classes.deescomms.ts

A communications module for enabling DOM-based messaging and synchronization across browser tabs and workers.

import * as plugins from './dees-comms.plugins.js';

let BroadcastChannel = globalThis.BroadcastChannel;
if (!BroadcastChannel) {
  BroadcastChannel = plugins.BroadCastChannelPolyfill as any;
}

/**
 * a comm class for client side communication between workers and tabs.
 */
export class DeesComms {
  private broadcastChannel = new BroadcastChannel('dees-comms');
  
  // sending messages
  public typedrouter = new plugins.typedrequest.TypedRouter();
  public typedtarget = new plugins.typedrequest.TypedTarget({
    postMethodWithTypedRouter: async (messageArg) => {
      this.postMessage(messageArg);
    },
    typedRouterRef: this.typedrouter,
  });

  // receiving messages
  constructor() {
    this.broadcastChannel.onmessage = async (eventArg) => {
      const message = (eventArg as any).method ? eventArg : eventArg.data;
      console.log(JSON.stringify(message));
      // Skip hooks for broadcast-received messages to prevent infinite loops
      // when traffic logging hooks are set up globally
      const response = await this.typedrouter.routeAndAddResponse(message, { skipHooks: true });
      if (response && !response.error) {
        this.postMessage(response);
      } else {
        // console.log(response);
      }
    };
  }

  /**
   * creates a typedrequest with this classes postMessage as postMethod
   */
  public createTypedRequest<T extends plugins.typedrequestInterfaces.ITypedRequest>(
    methodName: T['method']
  ): plugins.typedrequest.TypedRequest<T> {
    const typedrequest = new plugins.typedrequest.TypedRequest(this.typedtarget, methodName);
    return typedrequest;
  }

  /**
   * posts a typedrequestmessage
   */
  public async postMessage<T = plugins.typedrequestInterfaces.ITypedRequest>(
    messageArg: T
  ): Promise<void> {
    this.broadcastChannel.postMessage(messageArg);
  }

  /**
   * subscribe to messages
   */
  public async createTypedHandler<T extends plugins.typedrequestInterfaces.ITypedRequest>(
    methodArg: T['method'],
    handlerFunction: plugins.typedrequest.THandlerFunction<T>
  ) {
    this.typedrouter.addTypedHandler(
      new plugins.typedrequest.TypedHandler<T>(methodArg, handlerFunction)
    );
  }
}