Javascript generator function for infinite fibonacci

fibonacci.js

function* fibonacci() {
  let x = 0
  let y = 1

  yield x
  yield y
  
  while (true) yield x < y ? x = x + y : y = x + y
}

const fib = fibonacci()

fib.next() // {value: 0, done: false}
fib.next() // {value: 1, done: false}
fib.next() // {value: 1, done: false}
fib.next() // {value: 2, done: false}
fib.next() // {value: 3, done: false}
fib.next() // {value: 5, done: false}