lodash/lodash.pluck/index.js

/**
 * lodash 3.1.2 (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'),
    toPath = require('lodash._topath'),
    isArray = require('lodash.isarray'),
    map = require('lodash.map');

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

/**
 * The base implementation of `_.property` without support for deep paths.
 *
 * @private
 * @param {string} key The key of the property to get.
 * @returns {Function} Returns the new function.
 */
function baseProperty(key) {
  return function(object) {
    return object == null ? undefined : object[key];
  };
}

/**
 * A specialized version of `baseProperty` which supports deep paths.
 *
 * @private
 * @param {Array|string} path The path of the property to get.
 * @returns {Function} Returns the new function.
 */
function basePropertyDeep(path) {
  var pathKey = (path + '');
  path = toPath(path);
  return function(object) {
    return baseGet(object, path, pathKey);
  };
}

/**
 * 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's 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 property value of `path` from all elements in `collection`.
 *
 * @static
 * @memberOf _
 * @category Collection
 * @param {Array|Object|string} collection The collection to iterate over.
 * @param {Array|string} path The path of the property to pluck.
 * @returns {Array} Returns the property values.
 * @example
 *
 * var users = [
 *   { 'user': 'barney', 'age': 36 },
 *   { 'user': 'fred',   'age': 40 }
 * ];
 *
 * _.pluck(users, 'user');
 * // => ['barney', 'fred']
 *
 * var userIndex = _.indexBy(users, 'user');
 * _.pluck(userIndex, 'age');
 * // => [36, 40] (iteration order is not guaranteed)
 */
function pluck(collection, path) {
  return map(collection, property(path));
}

/**
 * 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 !!value && (type == 'object' || type == 'function');
}

/**
 * Creates a function that returns the property value at `path` on a
 * given object.
 *
 * @static
 * @memberOf _
 * @category Utility
 * @param {Array|string} path The path of the property to get.
 * @returns {Function} Returns the new function.
 * @example
 *
 * var objects = [
 *   { 'a': { 'b': { 'c': 2 } } },
 *   { 'a': { 'b': { 'c': 1 } } }
 * ];
 *
 * _.map(objects, _.property('a.b.c'));
 * // => [2, 1]
 *
 * _.pluck(_.sortBy(objects, _.property(['a', 'b', 'c'])), 'a.b.c');
 * // => [1, 2]
 */
function property(path) {
  return isKey(path) ? baseProperty(path) : basePropertyDeep(path);
}

module.exports = pluck;