Arrow functions

let sumOfTwoNumbers=(a,b)=>{
  return a+b;
}
let sumOfTwoNumbers=(a,b)=>a+b
let checkEven=n=>n%2==0;

Named functions

function sumOfTwoNumbers (a,b){
  return a+b;
}

Function expression

let sumOfTwoNumbers=function (a,b){
 return a+b;
}
let sumOfTwoNumbers=(a,b)=>{
return a+b;
}
let sumOfTwoNumbers=(a,b)=> a+b;