lib/reduceRight.js


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import reduce from './reduce';

/**
 * Same as [`reduce`]{@link module:Collections.reduce}, only operates on `array` in reverse order.
 *
 * @name reduceRight
 * @static
 * @memberOf module:Collections
 * @method
 * @see [async.reduce]{@link module:Collections.reduce}
 * @alias foldr
 * @category Collection
 * @param {Array} array - A collection to iterate over.
 * @param {*} memo - The initial state of the reduction.
 * @param {AsyncFunction} iteratee - A function applied to each item in the
 * array to produce the next step in the reduction.
 * The `iteratee` should complete with the next state of the reduction.
 * If the iteratee complete with an error, the reduction is stopped and the
 * main `callback` is immediately called with the error.
 * Invoked with (memo, item, callback).
 * @param {Function} [callback] - A callback which is called after all the
 * `iteratee` functions have finished. Result is the reduced value. Invoked with
 * (err, result).
 * @returns {Promise} a promise, if no callback is passed
 */
export default function reduceRight (array, memo, iteratee, callback) {
    var reversed = [...array].reverse();
    return reduce(reversed, memo, iteratee, callback);
}