generate new test that did already exist & update all module snippets with declaration

test/createEventHub/createEventHub.js

@@ -0,0 +1,14 @@
+module.exports = createEventHub = () => ({
+hub: Object.create(null),
+emit(event, data) {
+(this.hub[event] || []).forEach(handler => handler(data));
+},
+on(event, handler) {
+if (!this.hub[event]) this.hub[event] = [];
+this.hub[event].push(handler);
+},
+off(event, handler) {
+const i = (this.hub[event] || []).findIndex(h => h === handler);
+if (i > -1) this.hub[event].splice(i, 1);
+}
+});