implement Observable.from()

Question

This is a follow-up on 57. create an Observable.

Suppose you have solved 57. create an Observable, here you are asked to implement a creation operator from().

From the document, from()

Creates an Observable from an Array, an array-like object, a Promise, an iterable object, or an Observable-like object.

Your from() should accept all above types.

from([1,2,3]).subscribe(console.log);
// 1
// 2
// 3

Note

1. Observable is already given for you, no need to create it.
2. for the problem here, Observable-like means Observable instance. Though in real-world you should check Symbol.observable

Code

/**
 * @param {Array | ArrayLike | Promise | Iterable | Observable} input
 * @return {Observable}
 */
function from(input) {
  // your code here
}

Related

• create an Observable
• implement Observable Subject

Source

Source From