'use strict'; var $ = require('../internals/export'); var aCallable = require('../internals/a-callable'); var aMap = require('../internals/a-map'); var MapHelpers = require('../internals/map-helpers'); var $TypeError = TypeError; var get = MapHelpers.get; var has = MapHelpers.has; var set = MapHelpers.set; // `Map.prototype.update` method // https://github.com/tc39/proposal-collection-methods $({ target: 'Map', proto: true, real: true, forced: true }, { update: function update(key, callback /* , thunk */) { var map = aMap(this); var length = arguments.length; aCallable(callback); var isPresentInMap = has(map, key); if (!isPresentInMap && length < 3) { throw new $TypeError('Updating absent value'); } var value = isPresentInMap ? get(map, key) : aCallable(length > 2 ? arguments[2] : undefined)(key, map); set(map, key, callback(value, key, map)); return map; } });