does indexOf() in js searches all the elements of an array to execute?

const arr = ['a','b','c']; 
for (let char of arr) {
  console.log(char);
}

I believe that time complexity of code above is O(n).

const arr = ['a','b','c']; 
for (let char of arr) {
  console.log(arr.indexOf(char);
}

However, does indexOf() search all the elements?
If does so, I believe time complexity of code above may be O(n^2)

I want to know whether indexOf() searches all the components as for loop.