How to identify the first iteration in a for..in loop

Question

We have a loop like this:

for (var prop in obj) {
   if (obj.hasOwnProperty(prop) {
      // Here need operation only for first iteration (1)
      // Other operations
   }
}

How can we identify first iteration in (1)?

Answer 1

you can use forEach

array.forEach((element,index) => {
    if(index==0){
        // first element
        }else{
          // not first element  
        }
      });