JavaScript Iterator
Introduction
An iterator is a pointer for traversing the elements of a data structure.
Examples
Syntax
const iterable = ["a", "b"]
const iterator = iterable[Symbol.iterator]()
console.log(iterator.next()) // { value: 'a', done: false }
console.log(iterator.next()) // { value: 'b', done: false }
console.log(iterator.next()) // { value: undefined, done: true }
TypeScript Interfaces
Expressed as interfaces in TypeScript notation:
interface Iterable {
[Symbol.iterator](): Iterator
}
interface Iterator {
next(): IteratorResult
}
interface IteratorResult {
value: any
done: boolean
}