lodash/internal/isIterateeCall.js

define(['./isArrayLike', './isIndex', '../lang/isObject'], function(isArrayLike, isIndex, isObject) {

  /**
   * Checks if the provided arguments are from an iteratee call.
   *
   * @private
   * @param {*} value The potential iteratee value argument.
   * @param {*} index The potential iteratee index or key argument.
   * @param {*} object The potential iteratee object argument.
   * @returns {boolean} Returns `true` if the arguments are from an iteratee call, else `false`.
   */
  function isIterateeCall(value, index, object) {
    if (!isObject(object)) {
      return false;
    }
    var type = typeof index;
    if (type == 'number'
        ? (isArrayLike(object) && isIndex(index, object.length))
        : (type == 'string' && index in object)) {
      var other = object[index];
      return value === value ? (value === other) : (other !== other);
    }
    return false;
  }

  return isIterateeCall;
});