comment-core-library/src/Promises.js

Javascript library for organizing and displaying danmaku comments

/**
 * Promises extra functionality
 * @license MIT
 * @author Jim Chen
 */
var Promises = (function( ) {

    var Promises = {};

    /**
     * Resolves as soon as any promise resolves in the order of the input array
     * 
     * @param arr - array of promises
     * @return promise that resolves if any one promise resolves and rejects
     *         if otherwise
     **/
    Promises.any = function (promises) {
        if (!Array.isArray(promises)) {
            // Is raw object or promise, resolve it directly
            return Promise.resolve(promises);
        }
        if (promises.length === 0) {
            // No promises to resolve so we think it failed
            return Promise.reject();
        }
        return new Promise(function (resolve, reject) {
            var hasResolved = false;
            var hasCompleted = 0;
            var errors = [];
            for (var i = 0; i < promises.length; i++) {
                promises[i].then(function (value) {
                    hasCompleted++;
                    if (!hasResolved) {
                        hasResolved = true;
                        resolve(value);
                    }
                }).catch((function (i) {
                    return function (e) {
                        hasCompleted++;
                        errors[i] = e;
                        if (hasCompleted === promises.length) {
                            // All promises have completed and we are in rejecting case
                            if (!hasResolved) {
                                reject(errors);
                            }
                        }
                    }
                })(i));
            }
        });
    };

    return Promises;
})();