Introduction to JavaScript Data Types

Primitive types

JavaScript provide six different data types that we call primitive because they are immutable in nature. These types are always passed by value, which means that we cannot modify them in-place. Additionally a null primitive is provided that represents the absence of an object value.

The primitive types are:

• undefined: A variable that has yet to be assigned a value.
• null: A variable that has yet to be assigned a value.
• Boolean: Logical entity that can be either true or false.
• Number: Represents double-precision 64-bit floating-point numbers.
• String: Textual data.
• BigInt: Large integers exceeding the safe limit of Numbers.
• Symbol: Unique atom values.

Notice here that unlike many other programming lanuages, strings are immutable in JavaScript. We cannot modify them in-place, but rather have to create new strings when manipulating them.