var DESCRIPTORS = require('../internals/descriptors');
+var FUNCTION_NAME_EXISTS = require('../internals/function-name').EXISTS;
+var uncurryThis = require('../internals/function-uncurry-this');
var defineProperty = require('../internals/object-define-property').f;
var FunctionPrototype = Function.prototype;
-var FunctionPrototypeToString = FunctionPrototype.toString;
-var nameRE = /^\s*function ([^ (]*)/;
+var functionToString = uncurryThis(FunctionPrototype.toString);
+var nameRE = /function\b(?:\s|\/\*[\S\s]*?\*\/|\/\/[^\n\r]*[\n\r]+)*([^\s(/]*)/;
+var regExpExec = uncurryThis(nameRE.exec);
var NAME = 'name';
// Function instances `.name` property
// https://tc39.es/ecma262/#sec-function-instances-name
-if (DESCRIPTORS && !(NAME in FunctionPrototype)) {
+if (DESCRIPTORS && !FUNCTION_NAME_EXISTS) {
defineProperty(FunctionPrototype, NAME, {
configurable: true,
get: function () {
try {
- return FunctionPrototypeToString.call(this).match(nameRE)[1];
+ return regExpExec(nameRE, functionToString(this))[1];
} catch (error) {
return '';
}