Save Every Task Change

Loading data is only half of persistence. Save the task array whenever a user changes it.

Add saveTasks() after each of these operations:

Adding

tasks.unshift(newTask);
saveTasks();
renderTasks();

Completing or reopening

task.completed = !task.completed;
saveTasks();
renderTasks();

Editing

task.title = title;
task.due = due;
task.priority = priority;
saveTasks();
renderTasks();

Deleting

tasks = tasks.filter((item) => item.id !== taskId);
saveTasks();
renderTasks();

The exact placement can vary with your existing functions. The important rule is simple: after the task data changes, save the current array.

Checkpoint: Add, complete, edit, and delete a task, refresh the page, and confirm that each change remains.