lodash/collection/invoke.js

import baseEach from '../internal/baseEach';
import isLength from '../internal/isLength';
import restParam from '../function/restParam';

/**
 * Invokes the method named by `methodName` on each element in `collection`,
 * returning an array of the results of each invoked method. Any additional
 * arguments are provided to each invoked method. If `methodName` is a function
 * it is invoked for, and `this` bound to, each element in `collection`.
 *
 * @static
 * @memberOf _
 * @category Collection
 * @param {Array|Object|string} collection The collection to iterate over.
 * @param {Function|string} methodName The name of the method to invoke or
 *  the function invoked per iteration.
 * @param {...*} [args] The arguments to invoke the method with.
 * @returns {Array} Returns the array of results.
 * @example
 *
 * _.invoke([[5, 1, 7], [3, 2, 1]], 'sort');
 * // => [[1, 5, 7], [1, 2, 3]]
 *
 * _.invoke([123, 456], String.prototype.split, '');
 * // => [['1', '2', '3'], ['4', '5', '6']]
 */
var invoke = restParam(function(collection, methodName, args) {
  var index = -1,
      isFunc = typeof methodName == 'function',
      length = collection ? collection.length : 0,
      result = isLength(length) ? Array(length) : [];

  baseEach(collection, function(value) {
    var func = isFunc ? methodName : (value != null && value[methodName]);
    result[++index] = func ? func.apply(value, args) : undefined;
  });
  return result;
});

export default invoke;