Javascript Data Types


A value in JavaScript is always of a certain type. For example, a string or a number.

There are eight basic data types in JavaScript. Here, we’ll cover them in general and in the next chapters we’ll talk about each of them in detail.

We can put any type in a variable. For example, a variable can at one moment be a string and then store a number:

// no error let message = "hello"; message = 123456;

Programming languages that allow such things, such as JavaScript, are called “dynamically typed”, meaning that there exist data types, but variables are not bound to any of them.

JavaScript provides different data types to hold different types of values. There are two types of data types in JavaScript.

  1. Primitive data type
  2. Non-primitive (reference) data type
typeof {name:'John', age:34} // Returns "object"
 typeof [1,2,3,4]             // Returns "object" (not "array", see note below)
 typeof null                  // Returns "object"
typeof function myFunc(){}   // Returns "function"

Example -