Parameterized Function – Part 2

Let’s continue Part 1 of Parameterized Functions.

Recursion Functions

• Recursion functions are those functions that call themselves repeatedly using different parameters.
• They generally call themselves repeatedly using loops until they reach a certain break-point/result.
  Below is an example. This is a very famous example of recursion.

var n:number = 8;
console.log("Factorial of " + n + " is " + factorial(n));
function factorial(num:number){
    if(num<=0){
        return 1;
    }
    else{
        return (num * factorial(num-1));
    }
}

Below is the output of above code:

Anonymous Functions

• These functions do not have name and cannot be reused.
• They function as normal functions like taking parameters and returning value.
  Below is an example:

var sum=function(num1:number, num2:number){
    return (num1+num2);
}
console.log("Sum is: " + sum(10,20));

Below is the output of above code. You can also print the value inside the function as well.

Lambda Functions

• They are like anonymous functions in TypeScript. They are called as Arrow Functions.
• We can pass parameters in these function and also write function’s statements in this, the way we wrote for other functions.
• The only difference is the Lambda Notation(=>).
• We generally use a single character to declare function parameters.

Lambda Expression
It is a one liner code which acts as a function.

Syntax for Lambda Expression:

(parameter1, parameter2,..) => function statements

Below is an example:

var n2:number = 20;
var sum=(n1:number, n3:number) => n2 + n1 + n3;
console.log("Sum is: " + sum(10,30));

Below is the output of above code:

Lambda Statement
It points to a block of code.
Below is the syntax for Lambda Statement:

(parameter1, parameter2,..) => {
    function statements
}

Below is an example:

var n2:number = 20;
var add=(n1:number, n3:number) => {
    var sum = n2 + n1 + n3;
    console.log("Sum is: " + sum);
}
add(100,30);

Below is the output of above code:

Function Constructor

• We can also define a function using JavaScript’s build in constructor called Function().
  It’s syntax:

var result = new Function(parameter1, parameter2,....)

Below is an example:

var add = new Function("num1", "num2", " return (num1 + num2)" );
var sum=add(10,20);
console.log("Sum is: " + sum);

Below is the output of above code: