Primitive data types in Javascript

Introduction

Primitive data types are the basic building blocks to store simple values in a program. They help us keep and use small pieces of information like numbers or words.

When you want to store a number like age or price.

When you want to store a short piece of text like a name or a city.

When you want to store true or false answers, like if a light is on or off.

When you want to store a single character or symbol.

When you want to store a special value like 'nothing' or 'unknown'.

Syntax

Javascript

let numberExample = 42;
let stringExample = "hello";
let booleanExample = true;
let undefinedExample;
let nullExample = null;
let symbolExample = Symbol('id');
let bigintExample = 9007199254740991n;

JavaScript has 7 primitive data types: number, string, boolean, undefined, null, symbol, and bigint.

Primitive values are stored directly and are immutable (cannot be changed).

Examples

Basic examples of number, string, and boolean types.

Javascript

let age = 30; // number
let name = "Alice"; // string
let isStudent = false; // boolean

undefined means a variable has no value yet; null means an intentional empty value.

Javascript

let unknownValue; // undefined
let emptyValue = null; // null

Symbol creates a unique identifier, useful for special keys.

Javascript

let uniqueId = Symbol('id');

BigInt stores very large integers beyond normal number limits.

Javascript

let bigNumber = 123456789012345678901234567890n;

Sample Program

This program shows all primitive data types in JavaScript with example values and prints them.

Javascript

console.log("Primitive Data Types Examples:");

let numberExample = 100;
let stringExample = "Hello World";
let booleanExample = true;
let undefinedExample;
let nullExample = null;
let symbolExample = Symbol('unique');
let bigintExample = 9007199254740991n;

console.log("Number:", numberExample);
console.log("String:", stringExample);
console.log("Boolean:", booleanExample);
console.log("Undefined:", undefinedExample);
console.log("Null:", nullExample);
console.log("Symbol:", symbolExample.toString());
console.log("BigInt:", bigintExample);

Important Notes

Time complexity: Accessing primitive values is very fast, constant time O(1).

Space complexity: Each primitive uses a small fixed amount of memory.

Common mistake: Confusing null and undefined; undefined means no value assigned, null means empty value assigned.

Use primitives for simple data. For collections or complex data, use objects or arrays.

Summary

Primitive data types store simple, single values like numbers or text.

JavaScript has 7 primitive types: number, string, boolean, undefined, null, symbol, and bigint.

Primitives are fast and use little memory, perfect for basic data storage.