var DESCRIPTORS = require('../internals/descriptors'); var defineProperty = require('../internals/object-define-property').f; var FunctionPrototype = Function.prototype; var FunctionPrototypeToString = FunctionPrototype.toString; var nameRE = /^\s*function ([^ (]*)/; var NAME = 'name'; // Function instances `.name` property // https://tc39.github.io/ecma262/#sec-function-instances-name if (DESCRIPTORS && !(NAME in FunctionPrototype)) { defineProperty(FunctionPrototype, NAME, { configurable: true, get: function () { try { return FunctionPrototypeToString.call(this).match(nameRE)[1]; } catch (error) { return ''; } } }); }