chore: update deps

src/utils/mitt.ts

@@ -0,0 +1,73 @@
+/**
+ * Mitt: Tiny functional event emitter / pubsub
+ *
+ * @name mitt
+ * @param {Array} [all] Optional array of event names to registered handler functions
+ * @returns {Function} The function's instance
+ */
+export default class Mitt {
+  private cache: Map<string, Array<(data: any) => void>>;
+  constructor(all = []) {
+    // A Map of event names to registered handler functions.
+    this.cache = new Map(all);
+  }
+
+  once(type: string, handler: Fn) {
+    const decor = (...args: any[]) => {
+      handler && handler.apply(this, args);
+      this.off(type, decor);
+    };
+    this.on(type, decor);
+    return this;
+  }
+
+  /**
+   * Register an event handler for the given type.
+   *
+   * @param {string|symbol} type Type of event to listen for, or `"*"` for all events
+   * @param {Function} handler Function to call in response to given event
+   */
+  on(type: string, handler: Fn) {
+    const handlers = this.cache.get(type);
+    const added = handlers && handlers.push(handler);
+    if (!added) {
+      this.cache.set(type, [handler]);
+    }
+  }
+
+  /**
+   * Remove an event handler for the given type.
+   *
+   * @param {string|symbol} type Type of event to unregister `handler` from, or `"*"`
+   * @param {Function} handler Handler function to remove
+   */
+  off(type: string, handler: Fn) {
+    const handlers = this.cache.get(type);
+    if (handlers) {
+      handlers.splice(handlers.indexOf(handler) >>> 0, 1);
+    }
+  }
+
+  /**
+   * Invoke all handlers for the given type.
+   * If present, `"*"` handlers are invoked after type-matched handlers.
+   *
+   * Note: Manually firing "*" handlers is not supported.
+   *
+   * @param {string|symbol} type The event type to invoke
+   * @param {*} [evt] Any value (object is recommended and powerful), passed to each handler
+   */
+  emit(type: string, evt: any) {
+    for (const handler of (this.cache.get(type) || []).slice()) handler(evt);
+    for (const handler of (this.cache.get('*') || []).slice()) handler(type, evt);
+  }
+
+  /**
+   * Remove all event handlers.
+   *
+   * Note: This will also remove event handlers passed via `mitt(all: EventHandlerMap)`.
+   */
+  clear() {
+    this.cache.clear();
+  }
+}