JavaScript Data Types

JavaScript classifies data types into primitive and non-primitive types. Here’s a detailed description with examples:

Primitive Data Types

Primitive data types hold fixed values and cannot be altered.

1. Number

The Number type in JavaScript handles both whole numbers and decimals.

• Example:
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    let age = 25; // Integer
    let price = 99.99; // Floating-point
    let notANumber = NaN; // Special number representing "Not a Number"
    let infinity = Infinity; // Special number for infinity

2. String

The String type stores text and supports ('), double ("), or backticks (`)

• Example:
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    let name = "Alice";
    let greeting = 'Hello';
    let message = `Welcome, ${name}!`; // Template literal with interpolation
  

3. Boolean

The Boolean type holds true or false values for logical operations.

• Example:
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    let isAdult = true;
    let hasPermission = false;
  

4. Undefined

An uninitialized variable in JavaScript has the type undefined.

• Example:
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    let uninitialized;
    console.log(uninitialized); // Output: undefined
  

5. Null

The null type signifies a deliberately empty value.

• Example:
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    let emptyValue = null;
    console.log(emptyValue); // Output: null
  

6. Symbol (ES6)

The Symbol type creates unique and immutable identifiers.

• Example:
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    let uniqueID = Symbol("id");
    console.log(uniqueID); // Output: Symbol(id)
  

7. BigInt (ES11)

The BigInt type is used for very large integers beyond the Number limit.

• Example:
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    let bigNumber = 1234567890123456789012345678901234567890n; // 'n' suffix indicates BigInt
    console.log(bigNumber);
  

Non-Primitive Data Types

Non-primitive types are objects that can store collections of data or more complex entities.

1. Object

Objects are collections of key-value pairs.

• Example:
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    let person = {
    name: "Alice",
    age: 25,
    isStudent: true
    };
    console.log(person.name); // Accessing properties
  

2. Array

An array is a special type of object used to store ordered lists of items.

• Example:
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    let colors = ["red", "green", "blue"];
    console.log(colors[0]); // Accessing the first element
  

3. Function

Functions are first-class objects in JavaScript and can be assigned to variables or passed as arguments.

• Example:
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    function greet(name) {
    return `Hello, ${name}!`;
    }
    console.log(greet("Alice"));
  

4. Date

The Date object allows manipulation and formatting of dates and times.

• Example:
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    let today = new Date();
    console.log(today.toDateString());
  

5. Map

A Map stores key-value pairs with any type of key.

• Example:
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    let map = new Map();
    map.set("name", "Alice");
    map.set("age", 25);
    console.log(map.get("name")); // Output: Alice
  

6. Set

A Set maintains a collection of distinct values without duplicates.

• Example:
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    let set = new Set([1, 2, 3, 2]);
    console.log(set); // Output: Set { 1, 2, 3 }
  

Type Checking

JavaScript has two main ways to check types:

1. typeof Operator
   Returns the type of a variable.

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     console.log(typeof 25); // Output: "number"
     console.log(typeof "Hello"); // Output: "string"
   

2. instanceof Operator
   Checks if an object is an instance of a specific class.

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     console.log([] instanceof Array); // Output: true