Introduction to functions in JavaScript

Function for adding two numbes and returning the result

function add(x,y)
  {
      return x+y;
  }
  let result = add(3,2)
  console.log(result);

Output

5

Handling Missing Parameters from within a function

function add(x,y)
  {
      if(y==undefined)
      {
          y=5;
      }
      return x+y;
  }
  let result = add(3)
  console.log(result);

Output

8

Function with default parameters

function add(x,y=10)
  {
      return x+y;
  }
  let result = add(3,5)
  console.log(result);

Output

8

Function with REST parameters

function add(...sat)
  {  
      let sum=0
     for(let x of sat)
     {
        sum+=x;
     }
     return sum;
  }
  let result = add(1,1,1,1,1,1)
  console.log(result);

Output

6

Passing an Array to a function

function add(iarr)
  {  
      let sum=0
     for(var x of iarr)
     {
        sum+=x;
     }
     return sum;
  }
  
  const arr = [1,2,3,4,5,6]
  let result = add(arr)
  console.log(result)

Output

21