function and anonymous function , type of function

function & anonymous function :

• The key difference between a function and an anonymous function lies in how they are defined and used. Let's break it down.

Named Function (Regular Function):

• A named function is a function that has a name by which it can be invoked.

const add = function (a: number, b: number): number {

  return a + b;

};

add(10, 20); // Calling the function using the variable name "add"

Anonymous Function:

• An anonymous function is a function without a name. It is typically used in situations where a function is passed as an argument or assigned to a variable.

const add = function (

a: number, b: number): number {

  return a + b;

};

add(10, 20); // Calling the function using the variable name "add"

 

Comparison:

Aspect	Named Function	Anonymous Function
Name	Has a name (e.g., add)	No name; assigned to a variable
Usage	Called by its name	Called using the variable it’s assigned to
Hoisting	Can be called before it’s defined	Cannot be called before it’s defined
Common Usage	Reusable code blocks, function declarations	Event handlers, callbacks, inline functions

                                  

Types of Functions in TypeScript:

Named Functions:

•  These functions have a name and can be called by that name.

function greet(name: string): string {

  return 'Hello' + name;

}

let message = greet ("ram");

console.log( message ); // hello ram

Arrow Functions :

• Arrow functions are a shorter way to write functions in JavaScript and TypeScript.
• They use the => syntax, 

// Arrow function  

const added = (a: number , b : number )=> a+b;

console.log( added (30,40));

Optional Parameters:

• An optional parameter is a parameter you can choose to provide or leave out calling a function.
• you make a parameter optional by adding a question mark (?) after its name.

  interface person {

    person_id :number;

    person_name: String ;

    person_dep :string;

    person_age?:number

  }

 

  let person : person ={

    person_id : 10,

    person_name: "ram",

    person_dep : "mca"

    // person_age?:number Optional Parameters

 

  }

  console.log( person );

 

Rest parameter :

• JavaScript (and TypeScript) allows you to represent an indefinite number of

arguments as an array.