Handle asynchronous tasks

src/containers/BackgroundTasks/BackgroundTasksProvider.test.tsx

@@ -9,77 +9,100 @@ import { Task, TaskData } from "./types";
 jest.useFakeTimers();
 
 describe("Background task provider", () => {
-  it("can queue a task", () => {
+  it("can queue a task", done => {
+    const handle = jest.fn<Promise<boolean>, []>(
+      () => new Promise(resolve => resolve(true))
+    );
     const onCompleted = jest.fn();
     const onError = jest.fn();
 
     const { result } = renderHook(useBackgroundTasks);
 
     const taskId = result.current.queue(Task.CUSTOM, {
-      handle: () => true,
+      handle,
       onCompleted,
       onError
     });
     expect(taskId).toBe(1);
+    expect(handle).not.toHaveBeenCalled();
     expect(onCompleted).not.toHaveBeenCalled();
     expect(onError).not.toHaveBeenCalled();
 
     jest.runOnlyPendingTimers();
 
-    expect(onCompleted).toHaveBeenCalled();
-    expect(onError).not.toHaveBeenCalled();
+    setImmediate(() => {
+      expect(handle).toHaveBeenCalled();
+      expect(onCompleted).toHaveBeenCalled();
+      expect(onError).not.toHaveBeenCalled();
+
+      done();
+    });
   });
 
-  it("can handle task error", () => {
+  it("can handle task error", done => {
+    const handle = jest.fn<Promise<boolean>, []>(
+      () =>
+        new Promise(() => {
+          throw new Error("dummy error");
+        })
+    );
     const onCompleted = jest.fn();
     const onError = jest.fn();
 
     const { result } = renderHook(useBackgroundTasks);
 
     result.current.queue(Task.CUSTOM, {
-      handle: () => {
-        throw new Error("dummy error");
-      },
+      handle,
       onCompleted,
       onError
     });
 
     jest.runOnlyPendingTimers();
 
-    expect(onCompleted).not.toHaveBeenCalled();
-    expect(onError).toHaveBeenCalled();
+    setImmediate(() => {
+      expect(handle).toHaveBeenCalled();
+      expect(onCompleted).not.toHaveBeenCalled();
+      expect(onError).toHaveBeenCalled();
+
+      done();
+    });
   });
 
-  it("can cancel task", () => {
+  it("can cancel task", done => {
     const onCompleted = jest.fn();
 
     const { result } = renderHook(useBackgroundTasks);
 
     const taskId = result.current.queue(Task.CUSTOM, {
-      handle: () => true,
+      handle: () => new Promise(resolve => resolve(true)),
       onCompleted
     });
 
-    jest.advanceTimersByTime(backgroundTasksRefreshTime - 1000);
+    // Cancel task before executing it
+    jest.advanceTimersByTime(backgroundTasksRefreshTime * 0.9);
     result.current.cancel(taskId);
 
     jest.runOnlyPendingTimers();
 
-    expect(onCompleted).not.toHaveBeenCalled();
+    setImmediate(() => {
+      expect(onCompleted).not.toHaveBeenCalled();
+
+      done();
+    });
   });
 
-  it("can queue multiple tasks", () => {
-    const responses = [
-      {
-        finished: false
-      },
-      {
-        finished: false
-      }
+  it("can queue multiple tasks", done => {
+    const responses: Array<Promise<boolean>> = [
+      new Promise(resolve =>
+        setTimeout(() => resolve(true), backgroundTasksRefreshTime * 1.4)
+      ),
+      new Promise(resolve =>
+        setTimeout(() => resolve(true), backgroundTasksRefreshTime * 2.1)
+      )
     ];
 
     const tasks: TaskData[] = responses.map(response => ({
-      handle: () => response.finished,
+      handle: () => response,
       onCompleted: jest.fn()
     }));
 
@@ -87,23 +110,30 @@ describe("Background task provider", () => {
 
     tasks.forEach(task => result.current.queue(Task.CUSTOM, task));
 
-    jest.runOnlyPendingTimers();
+    // Set time to backgroundTasksRefreshTime
+    jest.advanceTimersByTime(backgroundTasksRefreshTime + 100);
 
-    expect(tasks[0].onCompleted).not.toHaveBeenCalled();
-    expect(tasks[1].onCompleted).not.toHaveBeenCalled();
+    setImmediate(() => {
+      expect(tasks[0].onCompleted).not.toHaveBeenCalled();
+      expect(tasks[1].onCompleted).not.toHaveBeenCalled();
 
-    responses[0].finished = true;
+      // Set time to backgroundTasksRefreshTime * 2
+      jest.advanceTimersByTime(backgroundTasksRefreshTime);
 
-    jest.runOnlyPendingTimers();
+      setImmediate(() => {
+        expect(tasks[0].onCompleted).toHaveBeenCalled();
+        expect(tasks[1].onCompleted).not.toHaveBeenCalled();
 
-    expect(tasks[0].onCompleted).toHaveBeenCalled();
-    expect(tasks[1].onCompleted).not.toHaveBeenCalled();
+        // Set time to backgroundTasksRefreshTime * 3
+        jest.advanceTimersByTime(backgroundTasksRefreshTime);
 
-    responses[1].finished = true;
+        setImmediate(() => {
+          expect(tasks[1].onCompleted).toHaveBeenCalled();
+          expect(tasks[1].onCompleted).toHaveBeenCalled();
 
-    jest.runOnlyPendingTimers();
-
-    expect(tasks[1].onCompleted).toHaveBeenCalled();
-    expect(tasks[1].onCompleted).toHaveBeenCalled();
+          done();
+        });
+      });
+    });
   });
 });

src/containers/BackgroundTasks/BackgroundTasksProvider.tsx

@@ -2,7 +2,7 @@ import React from "react";
 
 import BackgroundTasksContext from "./context";
 import { handleTask, queueCustom } from "./tasks";
-import { QueuedTask, Task, TaskData } from "./types";
+import { QueuedTask, Task, TaskData, TaskStatus } from "./types";
 
 export const backgroundTasksRefreshTime = 15 * 1000;
 
@@ -12,7 +12,34 @@ export function useBackgroundTasks() {
 
   React.useEffect(() => {
     const intervalId = setInterval(() => {
-      tasks.current = tasks.current.filter(task => !handleTask(task));
+      const queue = async () => {
+        tasks.current = tasks.current.filter(
+          task => task.status !== TaskStatus.ENDED
+        );
+        try {
+          await Promise.all(
+            tasks.current.map(async task => {
+              let hasFinished: boolean;
+
+              try {
+                hasFinished = await handleTask(task);
+              } catch (error) {
+                throw error;
+              }
+              if (hasFinished) {
+                const taskIndex = tasks.current.findIndex(
+                  t => t.id === task.id
+                );
+                tasks.current[taskIndex].status = TaskStatus.ENDED;
+              }
+            })
+          );
+        } catch (error) {
+          throw error;
+        }
+      };
+
+      queue();
     }, backgroundTasksRefreshTime);
 
     return () => clearInterval(intervalId);

src/containers/BackgroundTasks/tasks.ts

@@ -1,17 +1,16 @@
-import { QueuedTask, TaskData } from "./types";
+import { QueuedTask, TaskData, TaskStatus } from "./types";
 
-export function handleTask(task: QueuedTask) {
-  let ok: boolean;
+export async function handleTask(task: QueuedTask): Promise<boolean> {
+  let ok = false;
   try {
-    ok = task.handle();
+    ok = await task.handle();
+    if (ok) {
+      task.onCompleted();
+    }
   } catch (error) {
     task.onError(error);
   }
 
-  if (ok) {
-    task.onCompleted();
-  }
-
   return ok;
 }
 
@@ -36,7 +35,8 @@ export function queueCustom(
       handle: data.handle,
       id,
       onCompleted: data.onCompleted,
-      onError: data.onError || handleError
+      onError: data.onError || handleError,
+      status: TaskStatus.PENDING
     }
   ];
 }

src/containers/BackgroundTasks/types.ts

@@ -1,16 +1,21 @@
 export enum Task {
   CUSTOM
 }
+export enum TaskStatus {
+  PENDING,
+  ENDED
+}
 
 export interface QueuedTask {
   id: number;
-  handle: () => boolean;
+  handle: () => Promise<boolean>;
+  status: TaskStatus;
   onCompleted: () => void;
   onError: (error: Error) => void;
 }
 
 export interface TaskData {
-  handle?: () => boolean;
+  handle?: () => Promise<boolean>;
   onCompleted?: () => void;
   onError?: () => void;
 }