when to use different loops in javascript code example

Example 1: javascript for loop

var colors=["red","blue","green"];
for (let i = 0; i < colors.length; i++) { 
  console.log(colors[i]);
}

Example 2: javascript loop through array

const array = [1, 2, 3, 4];

for(num of array) {
  console.log(num); 
}