lodash/lodash.has/index.js

/**
 * lodash 3.1.1 (Custom Build) <https://lodash.com/>
 * Build: `lodash modern modularize exports="npm" -o ./`
 * Copyright 2012-2015 The Dojo Foundation <http://dojofoundation.org/>
 * Based on Underscore.js 1.8.3 <http://underscorejs.org/LICENSE>
 * Copyright 2009-2015 Jeremy Ashkenas, DocumentCloud and Investigative Reporters & Editors
 * Available under MIT license <https://lodash.com/license>
 */
var baseGet = require('lodash._baseget'),
    baseSlice = require('lodash._baseslice'),
    toPath = require('lodash._topath'),
    isArray = require('lodash.isarray');

/** Used to match property names within property paths. */
var reIsDeepProp = /\.|\[(?:[^[\]]*|(["'])(?:(?!\1)[^\n\\]|\\.)*?\1)\]/,
    reIsPlainProp = /^\w*$/;

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

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

/**
 * Checks if `value` is a property name and not a property path.
 *
 * @private
 * @param {*} value The value to check.
 * @param {Object} [object] The object to query keys on.
 * @returns {boolean} Returns `true` if `value` is a property name, else `false`.
 */
function isKey(value, object) {
  var type = typeof value;
  if ((type == 'string' && reIsPlainProp.test(value)) || type == 'number') {
    return true;
  }
  if (isArray(value)) {
    return false;
  }
  var result = !reIsDeepProp.test(value);
  return result || (object != null && value in toObject(object));
}

/**
 * Converts `value` to an object if it is not one.
 *
 * @private
 * @param {*} value The value to process.
 * @returns {Object} Returns the object.
 */
function toObject(value) {
  return isObject(value) ? value : Object(value);
}

/**
 * Gets the last element of `array`.
 *
 * @static
 * @memberOf _
 * @category Array
 * @param {Array} array The array to query.
 * @returns {*} Returns the last element of `array`.
 * @example
 *
 * _.last([1, 2, 3]);
 * // => 3
 */
function last(array) {
  var length = array ? array.length : 0;
  return length ? array[length - 1] : undefined;
}

/**
 * Checks if `value` is the [language type](https://es5.github.io/#x8) of `Object`.
 * (e.g. arrays, functions, objects, regexes, `new Number(0)`, and `new String('')`)
 *
 * @static
 * @memberOf _
 * @category Lang
 * @param {*} value The value to check.
 * @returns {boolean} Returns `true` if `value` is an object, else `false`.
 * @example
 *
 * _.isObject({});
 * // => true
 *
 * _.isObject([1, 2, 3]);
 * // => true
 *
 * _.isObject(1);
 * // => false
 */
function isObject(value) {
  // Avoid a V8 JIT bug in Chrome 19-20.
  // See https://code.google.com/p/v8/issues/detail?id=2291 for more details.
  var type = typeof value;
  return type == 'function' || (!!value && type == 'object');
}

/**
 * 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));
    path = last(path);
    result = object != null && hasOwnProperty.call(object, path);
  }
  return result;
}

module.exports = has;