how to access second for loops index javascript code example

Example 1: javascript enumerate with index

const iterable = [...];
for (const [index, elem] in iterable.entries()) {
  f(index, elem);
}

// or
iterable.forEach((elem, index) => {
  f(index, elem);
});

Example 2: forloop in js

for(i = 0; i < x; ++i){
  //Loop, x can be replaced with any integer; 
}