I need some explanation on exercise Iterate over Arrays with map. The example code given in exercise is written below
var oldArray = [1, 2, 3];
var timesFour = oldArray.map(function(val){
return val * 4;
});
console.log(timesFour); // returns [4, 8, 12]
console.log(oldArray); // returns [1, 2, 3]
My Question is what exactly val parameter role is here. I am unable to understand through the explanation given in the exercise