JS: Value Types

Any value in JavaScript is either a Primitive type or Object type.

Variables don't have type.

primitive type

undefined

undefined is the only value of this type.

• JS: undefined

null

null is the only value of this type.

• JS: null

string

• JS: String Overview

number

Includes special value NaN and Infinity

• JS: NaN
• JS: Infinity

BigInt

big integer.

• JS: BigInt (tutorial)

boolean

true and false are the only possible values.

• JS: Boolean. true false

symbol

Always-unique value primarily for use as property keys.

• JS: Symbol Tutorial

Object type

object

e.g. {"x":3}

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

• JS: Object Type