KasmVNC/kasmweb/core/util/polyfill.js

/*
 * noVNC: HTML5 VNC client
 * Copyright (C) 2018 The noVNC Authors
 * Licensed under MPL 2.0 or any later version (see LICENSE.txt)
 */

/* Polyfills to provide new APIs in old browsers */

/* Object.assign() (taken from MDN) */
if (typeof Object.assign != 'function') {
    // Must be writable: true, enumerable: false, configurable: true
    Object.defineProperty(Object, "assign", {
        value: function assign(target, varArgs) { // .length of function is 2
            'use strict';
            if (target == null) { // TypeError if undefined or null
                throw new TypeError('Cannot convert undefined or null to object');
            }

            const to = Object(target);

            for (let index = 1; index < arguments.length; index++) {
                const nextSource = arguments[index];

                if (nextSource != null) { // Skip over if undefined or null
                    for (let nextKey in nextSource) {
                        // Avoid bugs when hasOwnProperty is shadowed
                        if (Object.prototype.hasOwnProperty.call(nextSource, nextKey)) {
                            to[nextKey] = nextSource[nextKey];
                        }
                    }
                }
            }
            return to;
        },
        writable: true,
        configurable: true
    });
}

/* CustomEvent constructor (taken from MDN) */
(() => {
    function CustomEvent(event, params) {
        params = params || { bubbles: false, cancelable: false, detail: undefined };
        const evt = document.createEvent( 'CustomEvent' );
        evt.initCustomEvent( event, params.bubbles, params.cancelable, params.detail );
        return evt;
    }

    CustomEvent.prototype = window.Event.prototype;

    if (typeof window.CustomEvent !== "function") {
        window.CustomEvent = CustomEvent;
    }
})();