Data-Types

Primitive Datatypes

1. Number
   • Represents both integer and floating-point numbers.
   • Example:

let integer = 42; let float = 3.14;

- Special values: `Infinity`, `-Infinity`, `NaN` (Not-a-Number).
	
	

1. String
   • Represents sequences of characters.
   • Can be defined using single quotes ('), double quotes ("), or backticks (`) for template literals.
   • Example:

let singleQuote = 'Hello';
let doubleQuote = "World";
let templateLiteral = `Hello, ${doubleQuote}!`;

3. Boolean
   • Represents logical values: true and false.
   • Example:

let isTrue = true; let isFalse = false;

4. Undefined

   • Represents a variable that has been declared but not assigned a value.

   • Example:

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

5. Null

   • Represents the intentional absence of any object value.

   • Example:

     let y = null;

6. Symbol (ES6)

   • Represents a unique and immutable value often used as object keys.

   • Example:

     let sym = Symbol('description');

7. BigInt (ES11)

   • Represents whole numbers larger than the maximum safe integer (Number.MAX_SAFE_INTEGER).

   • Example:

     let bigInt = 1234567890123456789012345678901234567890n;

Composite (Complex) Datatypes

1. Object

   • A collection of properties, where each property is a key-value pair.

   • Keys can be strings or symbols, and values can be any datatype.

   • If Keys are number data type then value is implicitly converted into strings.

   • Example:

     let obj = { name: 'Alice', age: 30, greet: function() { console.log('Hello!'); } };

2. Array

   • A list-like collection of elements, accessible via numerical indices.

   • Example:

     let arr = [1, 2, 3, 'four', { five: 5 }];

Special Datatypes

1. Functions

   • A callable object that encapsulates code to be executed.

   • Functions can be defined in various ways (function declarations, expressions, arrow functions).

   • Example:

     function greet() { return 'Hello!'; } let greetArrow = () => 'Hello!';

Type Conversion and Coercion

• Implicit Type Coercion: JavaScript automatically converts values from one datatype to another in certain operations.

  • Example:

    console.log('5' + 5); // '55' (string concatenation) console.log('5' - 2); // 3 (numeric subtraction)

• Explicit Type Conversion: Manually converting from one datatype to another using functions.

  • Example:

    let num = Number('123'); // Converts string to number let str = String(123); // Converts number to string