Update createEventHub.md

snippets/createEventHub.md

@@ -2,7 +2,7 @@
 
 Creates a pub/sub ([publish–subscribe](https://en.wikipedia.org/wiki/Publish%E2%80%93subscribe_pattern)) event hub with `emit`, `on`, and `off` methods.
 
-Instantiate a new `Map` object to allow any event type (including objects) to be the key, and also so `Object.prototype` property names are not resolved.
+Create an empty `hub` property using `Object.create(null)` to create a truly empty object that does not inherit properties from `Object.prototype` (which would be resolved if the event name matched one of the properties).
 
 For `emit`, resolve the array of handlers based on the `event` argument and then run
 each one with `Array.forEach()` by passing in the data as an argument.
@@ -14,31 +14,26 @@ For `off`, use `Array.findIndex()` to find the index of the handler in the event
 
 ```js
 const createEventHub = () => ({
-  hub: new Map(),
+  hub: Object.create(null),
   emit(event, data) {
-    (this.hub.get(event) || []).forEach(handler => handler(data));
+    (this.hub[event] || []).forEach(handler => handler(data));
   },
   on(event, handler) {
-    const handlers = this.hub.get(event);
-    if (!handlers) this.hub.set(event, []);
-    handlers.push(handler);
+    if (!this.hub[event]) this.hub[event] = [];
+    this.hub[event].push(handler);
   },
   off(event, handler) {
-    const handlers = this.hub.get(event);
-    const i = (handlers || []).findIndex(h => h === handler);
-    if (i > -1) handlers.splice(i, 1);
+    const i = (this.hub[event] || []).findIndex(h => h === handler);
+    if (i > -1) this.hub[event].splice(i, 1);
   }
 });
 ```
 
 ```js
 const fn = data => console.log(data);
-const obj = {};
-
 const hub = createEventHub();
+
 hub.on('message', fn); // subscribe a handler to listen for 'message' events
-hub.on(obj, fn); // subscribe a handler to listen for the object
 hub.emit('message', 'hello!'); // console logs 'hello!'
-hub.emit(obj, 'hello!'); // console logs 'hello!'
-hub.off('message', fn); // unsubscribe our handler from 'message', the obj event will still work
+hub.off('message', fn); // unsubscribe our handler from 'message'
 ```