Understanding JavaScript Data Types: A Comprehensive Guide to Primitive and Reference Types with Examples

JavaScript has several built-in data types, which can be categorized into two broad groups:
? Primitive Types
? Non-Primitive (Reference) Types.

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JavaScript Data Types

Type

Examples

Primitive Types

➀ Number JavaScript Data Types

Type	Examples
Primitive Types	➀ Number ➁ String ➂ Boolean ➃ Undefined ➄ Null
Non-Primitive Types	➀ Object ➁ Array ➂ Function

➁ String ➂ Boolean

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➃ Undefined

➄ Null

Non-Primitive Types

➀ Object ➁ Array

➂ Function

❐ Now write Primitive type with deatils
Primitive data types are immutable and stored by value.

let age = 25; // Integer
let pi = 3.14159; // Floating-point
let negativeNumber = -42; // Negative number
let exponential = 1.23e4; // 12300 in exponential notatio

✚ Number

let singleQuote = 'Hello, world!';
let doubleQuote = "JavaScript is awesome!";
let templateLiteral = `This is a template literal`;

let multiLine = `This is a multi-line string.`;
console.log(`Name: ${singleQuote}, Length: ${singleQuote.length}`);

✚ String

let isJavaScriptFun = true;
let isOver18 = false;

console.log(typeof isJavaScriptFun); // "boolean"
console.log(5 > 2); // true
console.log(10 === '10'); // false

✚ Boolean

➭ Represents a logical value: true or false.

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

✚ Undefined

➭ A variable is declared but not assigned a value.

let y = null;
console.log(y); // null
console.log(typeof y); // "object" (this is a quirk in JavaScript)

✚ Null

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➭ Represents the intentional absence of any value (empty or unknown).

❐ Now write Non-Primitive type with deatils
Non-primitive data types are mutable and stored by reference..

let person = {
  name: 'John',
  age: 30,
  isStudent: false,
  hobbies: ['reading', 'gaming'],
  address: {
    city: 'New York',
    zip: '10001',
  },
};

console.log(person.name); // "John"
console.log(person.address.city); // "New York"
console.log(typeof person); // "object"

✚ Object

let fruits = ['Apple', 'Banana', 'Cherry'];
let mixedArray = [1, 'Hello', true, null, undefined];

console.log(fruits[0]); // "Apple"
console.log(mixedArray.length); // 5
console.log(typeof fruits); // "object" (arrays are objects in JS)

✚ Array

function greet(name) {
  return `Hello, ${name}!`;
}

let sum = function(a, b) {
  return a + b;
};

let multiply = (x, y) => x * y;

console.log(greet('Alice')); // "Hello, Alice!"
console.log(sum(3, 4)); // 7
console.log(multiply(5, 6)); // 30
console.log(typeof greet); // "function"

✚ Function

➭ Represents a logical value: true or false.

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