JS: Value Types

Variables don't have type.

Any value in JavaScript is one of the following type.

undefined †

undefined is the only value of this type.

null †

null

• null is the only value of this type.

boolean †

true false are the only possible values.

JS: Boolean. true false

string †

e.g. "xyz"

• JS: String Overview

number †

e.g. 34

Includes special value NaN and Infinity

• JS: NaN
• JS: Infinity

BigInt †

new in JS2020

e.g. 34n

big integer.

xtodo

symbol †

Always-unique value primarily for use as property keys.

• JS: Symbol Tutorial

object

e.g. {"x":3}

The object type is a collection of key-value pairs, some with special purpose, such as function, date.

• JS: Object Type

† A value of these types are called Primitive Value.