From c411a60661b7750836d6b8abdc375193381bfff9 Mon Sep 17 00:00:00 2001
From: Nik Bezdzenariy <kartoshkinkapustin@gmail.com>
Date: Thu, 30 Apr 2026 13:18:27 +0200
Subject: [PATCH 1/4] feat: add deleteCompleted function

Implement deleteCompleted() in todos.mjs to remove all completed
tasks from the todos array using filter and in-place splice mutation.
---
 Sprint-3/todo-list/todos.mjs | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/Sprint-3/todo-list/todos.mjs b/Sprint-3/todo-list/todos.mjs
index f17ab6a25..0461100ed 100644
--- a/Sprint-3/todo-list/todos.mjs
+++ b/Sprint-3/todo-list/todos.mjs
@@ -26,4 +26,9 @@ export function toggleCompletedOnTask(todos, taskIndex) {
   if (todos[taskIndex]) {
     todos[taskIndex].completed = !todos[taskIndex].completed;
   }
+}
+
+export function deleteCompleted(todos) {
+  const remaining = todos.filter(todo => !todo.completed);
+  todos.splice(0, todos.length, ...remaining);
 }
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From f92e991126723fb73e200e70238caf3f2a23d90c Mon Sep 17 00:00:00 2001
From: Nik Bezdzenariy <kartoshkinkapustin@gmail.com>
Date: Thu, 30 Apr 2026 13:18:43 +0200
Subject: [PATCH 2/4] test: add unit tests for deleteCompleted

Add 3 test cases:
- Delete all completed tasks from mixed list
- Do nothing when no tasks are completed
- Empty list when all tasks are completed
---
 Sprint-3/todo-list/todos.test.mjs | 27 +++++++++++++++++++++++++++
 1 file changed, 27 insertions(+)

diff --git a/Sprint-3/todo-list/todos.test.mjs b/Sprint-3/todo-list/todos.test.mjs
index d6bf96414..d596d6703 100644
--- a/Sprint-3/todo-list/todos.test.mjs
+++ b/Sprint-3/todo-list/todos.test.mjs
@@ -130,3 +130,30 @@ describe("toggleCompletedOnTask()", () => {
   });
 });
 
+describe("deleteCompleted()", () => {
+  test("Delete all completed tasks", () => {
+    const todos = createMockTodos();
+    Todos.deleteCompleted(todos);
+    expect(todos).toHaveLength(2);
+    expect(todos[0].task).toEqual("Task 2 description");
+    expect(todos[1].task).toEqual("Task 4 description");
+  });
+
+  test("Does nothing when no task are completed", () => {
+    const todos = [
+      {task: "A", completed: false},
+      {task: "B", completed: false},
+    ];
+    Todos.deleteCompleted(todos);
+    expect(todos).toHaveLength(2);
+  });
+
+  test("Empties the list when all tasks are completed", () => {
+    const todos = [
+      {task: "A", completed: true},
+      {task: "B", completed: true},
+    ];
+    Todos.deleteCompleted(todos);
+    expect(todos).toHaveLength(0);
+  });
+});
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From 2150d0936899771379ce172f3ce8ce0a325353c2 Mon Sep 17 00:00:00 2001
From: Nik Bezdzenariy <kartoshkinkapustin@gmail.com>
Date: Thu, 30 Apr 2026 13:19:01 +0200
Subject: [PATCH 3/4] feat: add 'Delete completed tasks' button

Add button element with id 'delete-completed-btn' after the
todo list to trigger mass deletion of completed tasks.
---
 Sprint-3/todo-list/index.html | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/Sprint-3/todo-list/index.html b/Sprint-3/todo-list/index.html
index 4d12c4654..8178f455c 100644
--- a/Sprint-3/todo-list/index.html
+++ b/Sprint-3/todo-list/index.html
@@ -21,6 +21,8 @@ <h1>My ToDo List</h1>
     <ul id="todo-list" class="todo-list">      
     </ul>
 
+    <button id="delete-completed-btn">Delete completed tasks</button>
+
     <!-- 
       This is a template for the To-do list item. 
       It can simplify the creation of list item node in JS script.

From d8f4bedad5962f10519cbb8c89070e628d24cf79 Mon Sep 17 00:00:00 2001
From: Nik Bezdzenariy <kartoshkinkapustin@gmail.com>
Date: Thu, 30 Apr 2026 13:19:18 +0200
Subject: [PATCH 4/4] feat: wire delete-completed button click handler

Register click event listener on delete-completed-btn that calls
Todos.deleteCompleted() and re-renders the list.
---
 Sprint-3/todo-list/script.mjs | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/Sprint-3/todo-list/script.mjs b/Sprint-3/todo-list/script.mjs
index ba0b2ceae..14325649c 100644
--- a/Sprint-3/todo-list/script.mjs
+++ b/Sprint-3/todo-list/script.mjs
@@ -6,6 +6,7 @@ const todos = [];
 
 // Set up tasks to be performed once on page load
 window.addEventListener("load", () => {
+  document.getElementById("delete-completed-btn").addEventListener("click", deleteCompletedTasks);
   document.getElementById("add-task-btn").addEventListener("click", addNewTodo);
 
   // Populate sample data
@@ -73,4 +74,9 @@ function createListItem(todo, index) {
   });
 
   return li;
+}
+
+function deleteCompletedTasks() {
+  Todos.deleteCompleted(todos);
+  render();
 }
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