message-port-polyfill/lib/bundle.js

simple polyfill to MessageChannel and MessagePort API

(function (global, factory) {
    typeof exports === 'object' && typeof module !== 'undefined' ? factory(exports) :
    typeof define === 'function' && define.amd ? define(['exports'], factory) :
    (global = global || self, factory(global.MessagePortPolyfill = {}));
}(this, function (exports) { 'use strict';

    // polyfill MessagePort and MessageChannel
    class MessagePortPolyfill {
        constructor() {
            this.onmessage = null;
            this.onmessageerror = null;
            this.otherPort = null;
            this.onmessageListeners = [];
        }
        dispatchEvent(event) {
            if (this.onmessage) {
                this.onmessage(event);
            }
            this.onmessageListeners.forEach(listener => listener(event));
            return true;
        }
        postMessage(message) {
            if (!this.otherPort) {
                return;
            }
            this.otherPort.dispatchEvent({ data: message });
        }
        addEventListener(type, listener) {
            if (type !== 'message') {
                return;
            }
            if (typeof listener !== 'function' ||
                this.onmessageListeners.indexOf(listener) !== -1) {
                return;
            }
            this.onmessageListeners.push(listener);
        }
        removeEventListener(type, listener) {
            if (type !== 'message') {
                return;
            }
            const index = this.onmessageListeners.indexOf(listener);
            if (index === -1) {
                return;
            }
            this.onmessageListeners.splice(index, 1);
        }
        start() {
            // do nothing at this moment
        }
        close() {
            // do nothing at this moment
        }
    }
    class MessageChannelPolyfill {
        constructor() {
            this.port1 = new MessagePortPolyfill();
            this.port2 = new MessagePortPolyfill();
            this.port1.otherPort = this.port2;
            this.port2.otherPort = this.port1;
        }
    }
    /**
     * https://github.com/zloirock/core-js/blob/master/packages/core-js/internals/global.js
     */
    const globalObj = typeof window !== 'undefined' && window.Math === Math ? window :
        typeof self !== 'undefined' && self.Math === Math ? self :
            Function('return this')();
    function applyPolyfill() {
        globalObj.MessagePort = MessagePortPolyfill;
        globalObj.MessageChannel = MessageChannelPolyfill;
    }
    if (!globalObj.MessagePort || !globalObj.MessageChannel) {
        applyPolyfill();
    }

    exports.MessagePortPolyfill = MessagePortPolyfill;
    exports.MessageChannelPolyfill = MessageChannelPolyfill;
    exports.applyPolyfill = applyPolyfill;

    Object.defineProperty(exports, '__esModule', { value: true });

}));