chore: task scheduler

src/common/TaskScheduler.ts

@@ -0,0 +1,73 @@
+/* eslint-disable @typescript-eslint/no-unsafe-argument */
+/**
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+
+ * http://www.apache.org/licenses/LICENSE-2.0
+
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import { requestIdleCallback, cancelIdleCallback, DEFAULT_REQUEST_ID } from './utils/compatible'
+
+interface Task {
+  id: string
+  handler: () => void
+}
+
+export default class TaskScheduler {
+  private readonly _tasks: Task[]
+
+  private _requestIdleCallbackId = DEFAULT_REQUEST_ID
+
+  constructor (tasks?: Task[]) {
+    this._tasks = tasks ?? []
+    this._operateTasks()
+  }
+
+  private _operateTasks (fn?: () => void): void {
+    if (this._requestIdleCallbackId !== DEFAULT_REQUEST_ID) {
+      cancelIdleCallback(this._requestIdleCallbackId)
+      this._requestIdleCallbackId = DEFAULT_REQUEST_ID
+    }
+    fn?.()
+    this._requestIdleCallbackId = requestIdleCallback(deadline => { this._runTasks(deadline) })
+  }
+
+  private _runTasks (deadline: IdleDeadline): void {
+    while (deadline.timeRemaining() > 0 && this._tasks.length > 0) {
+      const task = this._tasks.shift()
+      task?.handler()
+    }
+    if (this._tasks.length > 0) {
+      this._requestIdleCallbackId = requestIdleCallback(deadline => { this._runTasks(deadline) })
+    }
+  }
+
+  addTask (task: Task): this {
+    this._operateTasks(() => {
+      const index = this._tasks.findIndex(t => t.id === task.id)
+      if (index > -1) {
+        this._tasks[index] = task
+      } else {
+        this._tasks.push(task)
+      }
+    })
+    return this
+  }
+
+  removeTask (id: string): this {
+    this._operateTasks(() => {
+      const index = this._tasks.findIndex(t => t.id === id)
+      if (index > -1) {
+        this._tasks.splice(index, 1)
+      }
+    })
+    return this
+  }
+}