dashjs/src/core/Utils.js

A reference client implementation for the playback of MPEG DASH via Javascript and compliant browsers.

/**
 * The copyright in this software is being made available under the BSD License,
 * included below. This software may be subject to other third party and contributor
 * rights, including patent rights, and no such rights are granted under this license.
 *
 * Copyright (c) 2013, Dash Industry Forum.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without modification,
 * are permitted provided that the following conditions are met:
 *  * Redistributions of source code must retain the above copyright notice, this
 *  list of conditions and the following disclaimer.
 *  * Redistributions in binary form must reproduce the above copyright notice,
 *  this list of conditions and the following disclaimer in the documentation and/or
 *  other materials provided with the distribution.
 *  * Neither the name of Dash Industry Forum nor the names of its
 *  contributors may be used to endorse or promote products derived from this software
 *  without specific prior written permission.
 *
 *  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS AS IS AND ANY
 *  EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 *  WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 *  IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
 *  INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 *  NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
 *  PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
 *  WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 *  ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 *  POSSIBILITY OF SUCH DAMAGE.
 */

/**
 * @class
 * @ignore
 */
class Utils {
    static mixin(dest, source, copy) {
        let s;
        let empty = {};
        if (dest) {
            for (let name in source) {
                if (source.hasOwnProperty(name)) {
                    s = source[name];
                    if (!(name in dest) || (dest[name] !== s && (!(name in empty) || empty[name] !== s))) {
                        if (typeof dest[name] === 'object' && dest[name] !== null) {
                            dest[name] = Utils.mixin(dest[name], s, copy);
                        } else {
                            dest[name] = copy(s);
                        }
                    }
                }
            }
        }
        return dest;
    }

    static clone(src) {
        if (!src || typeof src !== 'object') {
            return src; // anything
        }
        let r;
        if (src instanceof Array) {
            // array
            r = [];
            for (let i = 0, l = src.length; i < l; ++i) {
                if (i in src) {
                    r.push(Utils.clone(src[i]));
                }
            }
        } else {
            r = {};
        }
        return Utils.mixin(r, src, Utils.clone);
    }
}

export default Utils;