has.js

var baseGet = require('../internal/baseGet'),
    baseSlice = require('../internal/baseSlice'),
    isArguments = require('../lang/isArguments'),
    isArray = require('../lang/isArray'),
    isIndex = require('../internal/isIndex'),
    isKey = require('../internal/isKey'),
    isLength = require('../internal/isLength'),
    last = require('../array/last'),
    toPath = require('../internal/toPath');

/** Used for native method references. */
var objectProto = Object.prototype;

/** Used to check objects for own properties. */
var hasOwnProperty = objectProto.hasOwnProperty;

/**
 * Checks if `path` is a direct property.
 *
 * @static
 * @memberOf _
 * @category Object
 * @param {Object} object The object to query.
 * @param {Array|string} path The path to check.
 * @returns {boolean} Returns `true` if `path` is a direct property, else `false`.
 * @example
 *
 * var object = { 'a': { 'b': { 'c': 3 } } };
 *
 * _.has(object, 'a');
 * // => true
 *
 * _.has(object, 'a.b.c');
 * // => true
 *
 * _.has(object, ['a', 'b', 'c']);
 * // => true
 */
function has(object, path) {
  if (object == null) {
    return false;
  }
  var result = hasOwnProperty.call(object, path);
  if (!result && !isKey(path)) {
    path = toPath(path);
    object = path.length == 1 ? object : baseGet(object, baseSlice(path, 0, -1));
    if (object == null) {
      return false;
    }
    path = last(path);
    result = hasOwnProperty.call(object, path);
  }
  return result || (isLength(object.length) && isIndex(path, object.length) &&
    (isArray(object) || isArguments(object)));
}

module.exports = has;