JavaScript-Cohort54/1-JavaScript/Week3/assignment/ex4-observable.js at 515e3a3d02519030ae736de375d56742a883ead8 · HackYourAssignment/JavaScript-Cohort54 · GitHub

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
function createObservable() {
  const subscribers = new Set();

  function subscribe(listener) {
    if (typeof listener !== "function") {
      return { unsubscribe() {} };
    }
    subscribers.add(listener);

    return {
      unsubscribe() {
        subscribers.delete(listener);
      },
    };
  }

  function notify(message) {
    // snapshot not needed with Set iteration, but this is fine
    subscribers.forEach((fn) => fn(message));
  }

  return { subscribe, notify };
}

module.exports = createObservable;
function createObservable() {
  const subscribers = [];

  function subscribe(listener) {
    subscribers.push(listener);
    return {
      unsubscribe() {
        const index = subscribers.indexOf(listener);
        if (index !== -1) {
          subscribers.splice(index, 1);
        }
      },
    };
  }

  function notify(message) {
    for (const listener of subscribers) {
      listener(message);
    }
  }

  return { subscribe, notify };
}

module.exports = createObservable;