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.[3]
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