Reserved Keyword In Javascript?
Javascript has a Predefined Collection of reserved keywords that can not be used as variables Name, Labels or Function, and Class Name.

ECMA Script: 1 😊
- break
- catch
- case
- class
- const
- continue
- debugger
- default
- delete
- do
- else
- enum
- export
- extends
- false
- finally
- for
- function
- if
- import
- in
- new
- null
- return
- super
- switch
- this
- throw
- true
- try
- typeof
- var
- void
- while
- with
ECMA Script: 2 😍
Add 24 additional reserved keywords in javascript.
new keywords denote by *
- abstract*
- boolean*
- break*
- byte*
- case*
- catch*
- char*
- class
- const*
- continue*
- debugger
- default*
- delete*
- do*
- double
- else*
- enum
- export
- extends
- false*
- final*
- finally*
- float*
- for*
- function*
- goto*
- if
- implements
- import
- in
- instanceof*
- int*
- interface*
- long*
- native*
- new
- null
- package*
- private*
- protected*
- public*
- return
- short*
- static*
- super
- switch
- synchronized*
- this
- throw
- throws*
- transient*
- true
- try
- typeof
- var
- void
- volatile*
- while
- with
ECMA Script: 5 😍
No change since ECMAScript 3
ECMAScript 5 remove int, char, goto, long, final, float, short, double, native, throws, boolean, abstract, volatile, transient, and synchronized.
Add 2 additional reserved keywords in javascript.
- break
- catch
- case
- class
- const
- continue
- debugger
- default
- delete
- do
- else
- enum
- export
- extends
- false
- finally
- for
- function
- if
- implements
- import
- in
- instanceof
- interface
- let*
- new
- null
- package
- private
- protected
- public
- return
- static
- super
- switch
- this
- throw
- true
- try
- typeof
- var
- void
- while
- with
- yield*
ECMA Script: 6
- await
- break
- case
- catch
- class
- const
- continue
- debugger
- default
- delete
- do
- else
- export
- extends
- finally
- for
- function
- if
- import
- in
- instanceof
- new
- return
- super
- switch
- this
- throw
- try
- typeof
- var
- void
- while
- with
- yield
Note:
The following keywords are not reserved, but when you use strict mode on javascript, that time shows an error.
- implements
- interface
- let
- package
- private
- protected
- public
- static
Other:
- true
- false
- null
- undefined
Reference:
Wrong ✖️
"use strict"function true(){} //Show Error In Strict Modelet await = 'rajdeep singh'; // Show Error with and without Strict Modelet case = 122 // Show Error with and without Strict Mojavade

Conclusion:
Javascript reserved keywords can not be used as a variable Name, Label or Function, and Class Name when using a named variable that shows SyntaxError.
If Any queries, mistakes, and Suggestions. Plz, tell me in the comment box.