javascript - How to output each number consecutively in an index every second?

Question

I have the following loop:

for (let index = 0; index < 4; index++) {  
  setInterval(function() {
    console.log(index)
  }, 1000);
}

Answer 1

Here's a more-or-less-but-rather-more elegant solution using a generator function.

Generator functions are useful here, as their execution can be paused by yield, and resumed by calling the generator object's next method:

function* logger() {
  while (true) {
    for (let index = 0; index < 4; index++) {
      console.log(index)
      yield
    }
  }
}

let generator = logger()
setInterval(() => generator.next(), 1000)