Common: Fix race condition during completion of recurrent task

Issue #13

Author: xuhcc

CHANGELOG.md

@@ -2,6 +2,7 @@
 
 ## 1.6.1
 
+- Mobile, Web: Fix task duplication during completion of recurrent task.
 - Mobile: Upgraded datepicker plugin.
 - Mobile, Web: Upgraded jsTodoTxt to version 0.10.0.
 - Web: Fixed styles for chrome browser.

src/app/task-list/task-list.component.ts

@@ -256,13 +256,21 @@ export class TaskListComponent implements OnInit, OnDestroy {
             this.postponeTask(task)
             return
         }
+        let recurDone: Promise<void>
         if (task.due && task.rec && !task.completed) {
+            // Create a copy if task is recurrent
+            // and wait for append operation to complete
             const newTask = task.recur()
-            this.todoFile.appendTask(newTask)
+            recurDone = this.todoFile.appendTask(newTask)
+        } else {
+            // Otherwise resolve immediately
+            recurDone = Promise.resolve()
         }
-        task.toggleComplete()
-        this.refreshTaskList()
-        this.todoFile.replaceTask(task.id, task)
+        recurDone.then(() => {
+            task.toggleComplete()
+            this.refreshTaskList()
+            this.todoFile.replaceTask(task.id, task)
+        })
     }
 
     postponeTask(task: Task) {