update

node_modules/mitt/src/index.js

@@ -0,0 +1,61 @@
+// @flow
+// An event handler can take an optional event argument
+// and should not return a value
+type EventHandler = (event?: any) => void;
+type WildCardEventHandler = (type: string, event?: any) => void
+
+// An array of all currently registered event handlers for a type
+type EventHandlerList = Array<EventHandler>;
+type WildCardEventHandlerList = Array<WildCardEventHandler>;
+// A map of event types and their corresponding event handlers.
+type EventHandlerMap = {
+  '*'?: WildCardEventHandlerList,
+  [type: string]: EventHandlerList,
+};
+
+/** Mitt: Tiny (~200b) functional event emitter / pubsub.
+ *  @name mitt
+ *  @returns {Mitt}
+ */
+export default function mitt(all: EventHandlerMap) {
+	all = all || Object.create(null);
+
+	return {
+		/**
+		 * Register an event handler for the given type.
+		 *
+		 * @param  {String} type	Type of event to listen for, or `"*"` for all events
+		 * @param  {Function} handler Function to call in response to given event
+		 * @memberOf mitt
+		 */
+		on(type: string, handler: EventHandler) {
+			(all[type] || (all[type] = [])).push(handler);
+		},
+
+		/**
+		 * Remove an event handler for the given type.
+		 *
+		 * @param  {String} type	Type of event to unregister `handler` from, or `"*"`
+		 * @param  {Function} handler Handler function to remove
+		 * @memberOf mitt
+		 */
+		off(type: string, handler: EventHandler) {
+			if (all[type]) {
+				all[type].splice(all[type].indexOf(handler) >>> 0, 1);
+			}
+		},
+
+		/**
+		 * Invoke all handlers for the given type.
+		 * If present, `"*"` handlers are invoked after type-matched handlers.
+		 *
+		 * @param {String} type  The event type to invoke
+		 * @param {Any} [evt]  Any value (object is recommended and powerful), passed to each handler
+		 * @memberOf mitt
+		 */
+		emit(type: string, evt: any) {
+			(all[type] || []).slice().map((handler) => { handler(evt); });
+			(all['*'] || []).slice().map((handler) => { handler(type, evt); });
+		}
+	};
+}