lodash/keys.js

define(['./internal/baseHas', './internal/baseKeys', './internal/indexKeys', './isArrayLike', './internal/isIndex', './internal/isPrototype'], function(baseHas, baseKeys, indexKeys, isArrayLike, isIndex, isPrototype) {

  /**
   * Creates an array of the own enumerable property names of `object`.
   *
   * **Note:** Non-object values are coerced to objects. See the
   * [ES spec](http://ecma-international.org/ecma-262/6.0/#sec-object.keys)
   * for more details.
   *
   * @static
   * @memberOf _
   * @category Object
   * @param {Object} object The object to query.
   * @returns {Array} Returns the array of property names.
   * @example
   *
   * function Foo() {
   *   this.a = 1;
   *   this.b = 2;
   * }
   *
   * Foo.prototype.c = 3;
   *
   * _.keys(new Foo);
   * // => ['a', 'b'] (iteration order is not guaranteed)
   *
   * _.keys('hi');
   * // => ['0', '1']
   */
  function keys(object) {
    var isProto = isPrototype(object);
    if (!(isProto || isArrayLike(object))) {
      return baseKeys(object);
    }
    var indexes = indexKeys(object),
        skipIndexes = !!indexes,
        result = indexes || [],
        length = result.length;

    for (var key in object) {
      if (baseHas(object, key) &&
          !(skipIndexes && (key == 'length' || isIndex(key, length))) &&
          !(isProto && key == 'constructor')) {
        result.push(key);
      }
    }
    return result;
  }

  return keys;
});