What is an iterator?An iterator is an interface that provides a unified access mechanism for various data structures. Any data structure can complete the traversal operation as long as the iterator interface is deployed.ES6 created a new traversal command for...of loop, which natively has a data structure with the iterator interface (which can be traversed with for...of). Contains Array, Arguments, Set, Map, String, TypedArray, NodeList. Of course, you can also implement this interface manually, which is convenient for practical use.