Data in JavaScript

In programming, a concept of data type is important to label and classify any digital information given. This is important because the program must know the characteristics of the information because a computer cannot understand the information given.

Therefore, different data in programming have data types.

The Data Types in JavaScript

There are two sub-groups of data types: primitive and non-primitive

Primitive: Primitive data types are the most basic data types in JavaScript. They are immutable, meaning their values cannot be changed once created. Each primitive type represents a single value.

Non-Primitive: Non-primitive data types, also known as reference types, are more complex. They can hold collections of values and more complex entities. Unlike primitive types, non-primitive types are mutable, meaning their values can be changed.

• Immutability: Primitive types are immutable, while non-primitive types are mutable.

• Storage: Primitive types store the actual value, whereas non-primitive types store references to the values.

Primitive Data Types

String: Represents textual data.

let name = "Alice";

Number: Represents both integer and floating-point (approximation of real) numbers.

let age = 30;
let price = 19.99;

Boolean: Represents a logical entity and can have two values: true or false.

let isStudent = true;

Undefined: A variable that has been declared but not assigned a value.

let x;
console.log(x); // undefined

Null: Represents the intentional absence of any object value.

let y = null;

Symbol: A unique and immutable primitive value, often used as keys for object properties.

let sym = Symbol('description');

BigInt: Represents integers with arbitrary precision.

let bigNumber = BigInt(1234567890123456789012345678901234567890n);

In this introductory programming course, we will not be learning non-primitive data types.

Recommended Readings

• Data Types (Link)