lazy multidimensional iterator.js

// write iterator class MyIterator(input)
// that has hasNext(), and next(), and can appropriately deal with multidimensional arrays

class MyIterator {

	#stack 
	#cachedNext
	#hasNext = false

	constructor(input){
		this.#stack = [input.values()]
	}

	hasNext(){
		if (this.#hasNext){
			return true
		}
		try {
			this.#cachedNext = this.next()
			return (this.#hasNext = true)
		} catch (e) {
			return (this.#hasNext = false)
		}
	}

	next(){
		if (this.#hasNext){
			this.#hasNext = false
			return this.#cachedNext
		}
		while (this.#stack.length){
			const iterator = this.#stack[this.#stack.length - 1]
			const next = iterator.next()
			if (next.done){
				this.#stack.pop()
				continue
			}
			const val = next.value
			if (val instanceof Array){
				this.#stack.push(val.values())
				continue
			}
			return val
		}
		throw "Error, no more array elements exist"
	}
}

console.log('Iterating Test Case 1')
const it = new MyIterator([
	[2,4],
	[6,[8,10],12],
	[[[14]]],
	[],[],[undefined],
	16
])
while (it.hasNext()){
	console.log(it.next())
}


console.log('Iterating Test Case 2')
const it2 = new MyIterator([
	[1,2,3,4,5],
	[6,[7,8,[9],10],12],
	[[[13,14,[15]]]],
	[],[16],[undefined],
	null,
	NaN
])
while (it2.hasNext()){
	it2.hasNext();it2.hasNext();it2.hasNext()
	console.log(it2.next())
}