feat(h5): $emit、$on、$off、$once

packages/uni-api/src/index.ts

 export * from './service/base/base64'
 export * from './service/base/upx2px'
 export * from './service/base/interceptor'
+export * from './service/base/eventBus'
 
 export * from './service/context/createVideoContext'
 export * from './service/context/createMapContext'

packages/uni-api/src/protocols/base/eventBus.ts

-export const $on: ProtocolOptions<String | Array<String> | Function>[] = [
+export const API_ON = '$on'
+export type API_TYPE_ON = typeof uni.$on
+export const OnProtocol: ProtocolOptions<String | Function>[] = [
   {
     name: 'event',
-    type: [String, Array],
+    type: String,
     required: true,
   },
   {
@@ -11,20 +13,27 @@ export const $on: ProtocolOptions<String | Array<String> | Function>[] = [
   },
 ]
 
-export const $once = $on
+export const API_ONCE = '$once'
+export type API_TYPE_ONCE = typeof uni.$once
+export const OnceProtocol = OnProtocol
 
-export const $off: ProtocolOptions<String | Array<String> | Function>[] = [
-  {
-    name: 'event',
-    type: [String, Array],
-  },
-  {
-    name: 'callback',
-    type: Function,
-  },
-]
+export const API_OFF = '$off'
+export type API_TYPE_OFF = typeof uni.$off
+export const OffProtocol: ProtocolOptions<String | Function | Array<String>>[] =
+  [
+    {
+      name: 'event',
+      type: [String, Array],
+    },
+    {
+      name: 'callback',
+      type: Function,
+    },
+  ]
 
-export const $emit: ProtocolOptions<String>[] = [
+export const API_EMIT = '$emit'
+export type API_TYPE_EMIT = typeof uni.$emit
+export const EmitProtocol: ProtocolOptions<String>[] = [
   {
     name: 'event',
     type: String,

packages/uni-api/src/service/base/eventBus.ts

+import { defineSyncApi } from '../../helpers/api'
+import {
+  API_ON,
+  API_OFF,
+  API_EMIT,
+  API_ONCE,
+  API_TYPE_ON,
+  API_TYPE_OFF,
+  API_TYPE_EMIT,
+  API_TYPE_ONCE,
+  OnProtocol,
+  OffProtocol,
+  EmitProtocol,
+  OnceProtocol,
+} from '../../protocols/base/eventBus'
+
+type EventName = string | number | symbol
+type EventCallback = (...args: any) => any
+type EventStopHandler = () => void
+
+class Emitter {
+  private eventMap: Map<EventName, Array<EventCallback>>
+
+  constructor() {
+    this.eventMap = new Map()
+  }
+
+  on = (name: EventName, callback: EventCallback): EventStopHandler => {
+    if (!this.eventMap.has(name)) {
+      this.eventMap.set(name, [])
+    }
+
+    this.eventMap.get(name)!.push(callback)
+
+    return () => this.off(name, callback)
+  }
+
+  once = (name: EventName, callback: EventCallback): EventStopHandler => {
+    const listener = (...args: any[]) => {
+      this.off(name, listener)
+      callback(...args)
+    }
+
+    this.on(name, listener)
+
+    return () => this.off(name, listener)
+  }
+
+  emit = (name: EventName, ...args: any[]): void => {
+    const cbs = this.eventMap.get(name)
+    if (cbs instanceof Array) {
+      cbs.forEach((cb) => {
+        typeof cb === 'function' && cb(...args)
+      })
+    }
+  }
+
+  off = (names?: EventName | EventName[], callback?: EventCallback): void => {
+    if (!names) {
+      this.eventMap.clear()
+      return
+    }
+    if (!(names instanceof Array)) {
+      names = [names]
+    }
+    if (typeof callback === 'function') {
+      names.forEach((name) => {
+        if (this.eventMap.has(name)) {
+          this.eventMap.set(
+            name,
+            this.eventMap.get(name)!.filter((cb) => cb !== callback)
+          )
+        }
+      })
+    } else {
+      names.forEach((name) => {
+        this.eventMap.delete(name)
+      })
+    }
+  }
+}
+
+const emitter = new Emitter()
+
+export const $on = defineSyncApi<API_TYPE_ON>(
+  API_ON,
+  (type, callback): EventStopHandler => emitter.on(type, callback),
+  OnProtocol
+)
+export const $once = defineSyncApi<API_TYPE_ONCE>(
+  API_ONCE,
+  (type, callback): EventStopHandler => emitter.once(type, callback),
+  OnceProtocol
+)
+export const $off = defineSyncApi<API_TYPE_OFF>(
+  API_OFF,
+  (type, callback) => {
+    emitter.off(type, callback)
+  },
+  OffProtocol
+)
+export const $emit = defineSyncApi<API_TYPE_EMIT>(
+  API_EMIT,
+  emitter.emit,
+  EmitProtocol
+)

packages/uni-h5/src/service/api/index.ts

@@ -76,5 +76,9 @@ export {
   canvasPutImageData,
   canvasToTempFilePath,
   getSelectedTextRange,
+  $on,
+  $off,
+  $once,
+  $emit,
 } from '@dcloudio/uni-api'
 //#endif