Let’s say you have an array and you’d like to cycle through its elements over and over. How would you go about it?

Let’s try with function generators, shall we?

function* cycleThrough(someArray) {
  while (true) yield* someArray
}

You can use it like this:

function* cycleThrough(someArray) {
  while (true) yield* someArray
}

const sortDirection = ['ASC', 'DESC', null]
const gen = cycleThrough(sortDirection)

console.log(gen.next().value) // 'ASC'
console.log(gen.next().value) // 'DESC'
console.log(gen.next().value) // null
console.log(gen.next().value) // 'ASC'

I know there are several ways to approach this problem, but I found this one the easiest and simplest way to construct a function that can iterate indefinitely over any array.

References

• Generator - MDN
• Iterators and generators - MDN
• How do I implement a cycle-through array with a generator function