Primitive and Non-primitive data-types in JavaScript

Variables hold values, and every value has a specific data type that defines the kind of information it holds. These data types are broadly categorized into two groups: Primitive Data Types and Non-Primitive Data Types. Let us discuss it one by one.

1. Primitive Data Types

Primitive data types are the built-in data types provided by JavaScript. They represent single values and are not mutable. JavaScript supports the following primitive data types:

1.1 Number:

Number data type in JavaScript can be used to hold decimal values as well as values without decimals.

Example: Below is an example.

    let x = 250;
    let y = 40.5;
    console.log("Value of x=" + x);
    console.log("Value of y=" + y);

Value of x=250
Value of y=40.5

1.2 String:

The string data type in JavaScript represents a sequence of characters that are surrounded by single or double quotes.

Example: Below is an example.

let str = 'Hello All';
let str1 = "Welcome to my new house";
console.log("Value of str=" + str);
console.log("Value of str1=" + str1);

Value of str=Hello All
Value of str1=Welcome to my new house

1.3 Undefined:

This means that a variable has been declared but has not been assigned a value, or it has been explicitly set to the value `undefined`.

Example: Below is an example.

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

Output:

undefined output

1.4 Boolean:

The boolean data type can accept only two values i.e. true and false.

Example: Below is an example.

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

Output:

boolean output

1.5 Null:

This data type can hold only one possible value that is null.

Example: Below is an example.

let x = null;
    console.log("Value of x=" + x);

Value of x=null

1.6 BigInt:

BigInt data type can represent numbers greater than 2⁵³-1 which helps to perform operations on large numbers. The number is specified by writing ‘n’ at the end of the value

Example: Below is an example.

let bigNum = 123422222222222222222222222222222222222n
console.log(bigNum)

123422222222222222222222222222222222222n

1.7 Symbol:

Symbol data type is used to create objects which will always be unique. these objects can be created using Symbol constructor.

Example: Below is an example.

let sym = Symbol("Hello")
console.log(typeof(sym));
console.log(sym);

symbol
Symbol(Hello)

2. Non-primitive Data Types

Non-primitive data types, also known as reference types, are objects and derived data types. They can store collections of values or more complex entities. The two key non-primitive data types in JavaScript are:

Below is a list of Non-primitive data types.

2.1 Object:

An object in Javascript is an entity having properties and methods. Everything is an object in javascript.

How to create an object in javascript:

• Using Constructor Function to define an object:

// Create an empty generic object
let obj = new Object();

// Create a user defined object
let mycar = new Car();

• Using Literal notations to define an object:

// An empty object
let square = {};

// Here a and b are keys and
// 20 and 30 are values
let circle = {a: 20, b: 30};

Example: Below is an example.

// Creating object with the name person
    let person = {
        firstName: "Luiza",
        lastName: "Shaikh",
    };

    // Print the value of object on console
    console.log(person.firstName 
        + "  " + person.lastName);

Luiza  Shaikh

2.2 Array:

With the help of an array, we can store more than one element under a single name.

Ways to declare a single-dimensional array:

// Call it with no arguments
let a = new Array();

// Call it with single numeric argument
let b = new Array(10);

// Explicitly specify two or
// more array elements
let d = new Array(1, 2, 3, "Hello");

Example: Below is an example.

    let a = new Array();
    let b = new Array(10);
    let d = new Array(1, 2, 3, "Hello");
    console.log("value of a=" + a);
    console.log("value of b" + b);
    console.log("value of d=" + d);

value of a=
value of b,,,,,,,,,
value of d=1,2,3,Hello

Note: JavaScript does not support two-dimensional arrays. but we can do this by creating an array of an array.

Difference Between Primitive vs Non-Primitive