JavaScript/Reserved words

This page contains a list of reserved words in JavaScript, which cannot be used as names of variables, functions or other objects.

Reserved words used in JavaScript

Current list of keywords used in JavaScript Version 5.1:

abstract	arguments	boolean	break	byte
case	catch	char	class*	const
continue	debugger	default	delete	do
double	else	enum*	eval	export*
extends*	final	finally	float	for
function	goto	if	implements	import*
in	instanceof	int	interface	let
long	native	new	package	private
protected	public	return	short	static
super*	switch	synchronized	this	throw
throws	transient	try	typeof	var
void	volatile	while	with	yield

(*) new reserved words in ECMAScript5

A few other reserved words used in JavaScript represent literal values:

false

null

true

Words reserved for JavaScript in the future

Some words have been reserved according to the ECMAScript specification so that they cannot be used as variable names, although currently, they do not have any functionality. These keywords may or may not be reserved words for some ECMAScript specification, and are grouped according to their condition of being reserved.

Words that are always reserved

await

enum

Words that are reserved in strict mode

implements	private	static
interface	protected
package	public

Words that were reserved in ECMAScript standards 1-3

abstract[citation needed]	extends	native[citation needed]
boolean[citation needed]	final[citation needed]	short[citation needed]
byte[citation needed]	float[citation needed]	super
char[citation needed]	goto[citation needed]	synchronized[citation needed]
class	import	throws[citation needed]
const	int[citation needed]	transient[citation needed]
double[citation needed]	let	volatile[citation needed]
export	long[citation needed]