Valid Identifier in JavaScript

Let's first see what an Identifier is

An Identifier is a user-defined name or a sequence of characters in the programming languages to define a variable, function, or property. It can be any combination of characters, but the combination of characters has a certain boundary/ restriction.

In this article, we will see what an Identifier means in JavaScript and what all combinations of characters are allowed in JavaScript to define any variable, function, or property name.

An Identifier in JavaScript

JavaScript identifiers are case-sensitive and can contain Unicode letters, $, _, and digits (0-9), but may not start with a digit.

An identifier is not a String, as a String is data, while an identifier is part of your code. In JavaScript, there is no way to convert identifiers to strings, but sometimes it is possible to parse strings into identifiers.

We cannot use reserved keywords of JavaScript as an identifier.

Let's see some examples of valid identifiers

let name = "CapsCode" let Name = "CapsCode" //javascript variables are case sensitive let firstName = "John" //any combination of characters let _name="john" //can start with underscore let first_name = "john" //can contain underscore let name_="john" //can end with underscore let $name = "john" //can start with dollar let first$name = "john" //can contain dollar let name$ = "john" //can end with dollar let first123name = "john" //can contain number let name123 = "john" //can end with number

Let's see some examples of invalid identifiers

  1. JavaScript variables do not contain spaces.
let first name = "John" //SyntaxError
  1. JavaScript variables do not start with numbers.
let 1qw = "Rahul" //SyntaxError
  1. Can contain only $
let first#name = "john" //SyntaxError let name#="john" //SyntaxError let #name="john" //SyntaxError
  1. do not start with the number
let 123name = "john" //SyntaxError
  1. should not be reserved keywords
let switch = "john" //SyntaxError let export = "john" //SyntaxError let new = "john" //SyntaxError


This is a brief introduction to what an identifier is and the various ways to define/ create a valid identifier in JavaScript.

If you find this article useful, share this article. Someone could find it useful too. If you find anything technically inaccurate, please feel free to create an issue.

Hope it's a nice and informative read for you. VISIT https://www.capscode.in/blog TO LEARN MORE... See you in my next Blog article, Take care!!