JS: Primitive Value

Primitive Value

The following values are called “Primitive Value”.

• undefined
• null
• true, false
• number (includes NaN and Infinity )
• string [see JS: String Overview]
• symbol [see JS: Symbol Tutorial]

They are also called primitive types.

[see JS: Value Types]

Primitive Value Object Wrapper

Most primitive type have corresponding object of object type.

• JS: String Object
• JS: Number Object
• JS: Boolean Object
• JS: Symbol Object

The object is used as primitive value wrapper. This allows you to call methods on them, such as "abc".length or (34).toString().

You can create number, string, boolean, objects yourself. (but they are rarely needed.)

For example:

new String(arg) [see JS: String Constructor]

new Number(arg) [see JS: Number Constructor]

new Boolean(arg) [see JS: Boolean Constructor]

Reference

ECMAScript 2015 §Overview#sec-primitive-value