ui: scratchpad sidebar

packages/ui-default/bus.ts

@@ -0,0 +1,92 @@
+/* eslint-disable no-await-in-loop */
+
+const _hooks: Record<keyof any, Array<(...args: any[]) => any>> = {};
+
+function isBailed(value: any) {
+  return value !== null && value !== false && value !== undefined;
+}
+
+export type Disposable = () => void;
+export type VoidReturn = Promise<any> | any;
+
+export interface EventMap extends Record<string, any> {
+  'scratchpadEditorCreate': (editor, monaco) => any;
+}
+
+function getHooks<K extends keyof EventMap>(name: K) {
+  const hooks = _hooks[name] || (_hooks[name] = []);
+  if (hooks.length >= 2048) {
+    console.warn(
+      'max listener count (2048) for event "%s" exceeded, which may be caused by a memory leak',
+      name,
+    );
+  }
+  return hooks;
+}
+
+export function removeListener<K extends keyof EventMap>(name: K, listener: EventMap[K]) {
+  const index = (_hooks[name] || []).findIndex((callback) => callback === listener);
+  if (index >= 0) {
+    _hooks[name].splice(index, 1);
+    return true;
+  }
+  return false;
+}
+
+export function addListener<K extends keyof EventMap>(name: K, listener: EventMap[K]) {
+  getHooks(name).push(listener);
+  return () => removeListener(name, listener);
+}
+
+export function prependListener<K extends keyof EventMap>(name: K, listener: EventMap[K]) {
+  getHooks(name).unshift(listener);
+  return () => removeListener(name, listener);
+}
+
+export function once<K extends keyof EventMap>(name: K, listener: EventMap[K]) {
+  let dispose;
+  function _listener(...args: any[]) {
+    dispose();
+    return listener.apply(this, args);
+  }
+  _listener.toString = () => `// Once \n${listener.toString()}`;
+  dispose = addListener(name, _listener);
+  return dispose;
+}
+
+export function on<K extends keyof EventMap>(name: K, listener: EventMap[K]) {
+  return addListener(name, listener);
+}
+
+export function off<K extends keyof EventMap>(name: K, listener: EventMap[K]) {
+  return removeListener(name, listener);
+}
+
+export async function parallel<K extends keyof EventMap>(name: K, ...args: Parameters<EventMap[K]>): Promise<void> {
+  const tasks: Promise<any>[] = [];
+  for (const callback of _hooks[name] || []) {
+    tasks.push(callback.apply(this, args));
+  }
+  await Promise.all(tasks);
+}
+
+export function emit<K extends keyof EventMap>(name: K, ...args: Parameters<EventMap[K]>) {
+  return parallel(name, ...args);
+}
+
+export async function serial<K extends keyof EventMap>(name: K, ...args: Parameters<EventMap[K]>): Promise<void> {
+  const hooks = Array.from(_hooks[name] || []);
+  for (const callback of hooks) {
+    await callback.apply(this, args);
+  }
+}
+
+export async function bail<K extends keyof EventMap>(name: K, ...args: Parameters<EventMap[K]>): Promise<ReturnType<EventMap[K]>> {
+  const hooks = Array.from(_hooks[name] || []);
+  for (const callback of hooks) {
+    let result = callback.apply(this, args);
+    if (result instanceof Promise) result = await result;
+    if (isBailed(result)) return result;
+  }
+  return null;
+}