abort controller with progress

controller.js

function* controller (end) {
  let progress = 0
  
  while (1) {
    const value = yield progress
    
    if (value === end) {
      break
    }
    
    progress += value ?? 0
  }

  return progress
}
  
const signal = Symbol('controller.signal')
const it = controller(signal)

console.log(it.next()) // { value: 0, done: false } -> get the progress
console.log(it.next(1)) // { value: 1, done: false } -> increase the progress
console.log(it.next(signal)) // { value: 1, done: true } -> get the final progress