invoke.js

var baseEach = require('../internal/baseEach'),
    invokePath = require('../internal/invokePath'),
    isArrayLike = require('../internal/isArrayLike'),
    isKey = require('../internal/isKey'),
    restParam = require('../function/restParam');

/**
 * Invokes the method at `path` of 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 {Array|Function|string} path The path 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, path, args) {
  var index = -1,
      isFunc = typeof path == 'function',
      isProp = isKey(path),
      result = isArrayLike(collection) ? Array(collection.length) : [];

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

module.exports = invoke;