Function createObservers

Observers encapsulates a collection of connections to event emitters, like Evented, Mutable, Watches and the like. It therefor helps you to manage multiple event connections by grouping them - e.g. for cleaning all connections at once.

Example: _track a event connection_

import Observers from "apprt-core/Observers";
let eventSource = new Evented();
let observers = Observers();
// track connection to eventSource
observers.add(eventSource.on("event", ()=>{...}));

// if the connection needs to be cleaned call
observers.clean();
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Example: _group event connections_

import Observers from "apprt-core/Observers";
let eventSourceA = new Evented();
let eventSourceB = new Evented();
let observers = Observers();
// track connection to eventSourceA, but in group "a"
observers.group("a").add(eventSourceA.on("event", ()=>{ ... }));
// track connection to eventSourceB, but in group "b"
observers.group("b").add(eventSourceB.on("event", ()=>{ ... }));

// if "a" is not longer required
observers.group("a").clean();

// if "b" is not longer required (shows alternative)
observers.clean("b");

// if none of the connections are required anymore clean all
observers.clean();
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Example: _use the rebind functionality_

// The bind/rebind functionality helps to encapsulate the code to connect to an observable.
// When the observable target changes a simple call to 'bind'
// rexecutes the connection code and clears the old connection.

import Observers from "apprt-core/Observers";
let Controller = class {
     constructor() {
         this.events = [];
         this._observers = Observers({
             // rebind is executed if Observers.bind is called, and used to reconnect to a new source instance
             rebind: (observers, source) => {
                 observers.add(source.on("change", (evt) => {
                     this.events.push(evt);
                 }));
             }
         });
     }
     connect(eventSource) {
        // observe new event source
         this._observers.bind(eventSource);
     }
     disconnect() {
        // disconnect from event source
         this._observers.clean();
     }
 }
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