JS: Primitive Value

Primitive Value

A primitive value is a value whose Type is a primitive type.

The following values are “Primitive Values”.

• any Number (includes NaN and Infinity)
• any String
• any Symbol
• undefined
• null
• true, false

Primitive Value Object Wrapper

Most primitive type have corresponding object of object type.

• String Object
• Number Object
• Boolean Object
• Symbol Object

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

You can create number, string, boolean, objects yourself. (but is not useful.) For example:

new String(arg) 〔see String Constructor〕

new Number(arg) 〔see Number Constructor〕

new Boolean(arg) 〔see Boolean Constructor〕

Convert Primitive Value to Object

Use Object(val) 〔see Object Constructor〕