Most difficult project so far!

Hi @BBualdo, this is one way you can achieve the functionality of the todo list:

• In the text input section add an id to the checkbox and to the input:

<section class="todo-input-container">
  <div class="todo-input">
    <input
      id="add-task"
      class="checkbox"
      type="checkbox"
    />
    <input
      id="input-add-task"
      class="todo"
      placeholder="Create a new todo..."
    />
  </div>
</section>

• The "todo-list-container" section can be left empty, since the tasks will be added with js:

<section class="todo-list-container">
  <!--Tasks will be added with js-->
</section>

• In the "nav-bar-container" section you can do the following:

1. Add an id to the p element inside the "items-left", to be able to dynamically change its text according to the number of tasks.
2. Add the class "is-toggled" all button "All", since it will be selected by default.

<section class="nav-bar-container">
  <div class="items-left">
    <p id="items-count"><!--items left--></p>
  </div>
  <div class="categories">
    <button class="category-button is-toggled">All</button>
    <button class="category-button">Active</button>
    <button class="category-button">Completed</button>
  </div>
  <div class="clear-completed">
    <button class="clear-completed-button">Clear Completed</button>
  </div>
</section>

Now we go with the Javascript code:

// Elements
const todoListContainer = document.querySelector(".todo-list-container");
const checkToAddTask = document.getElementById("add-task");
const inputAddTask = document.getElementById("input-add-task");
const categoryButtons = document.querySelectorAll(".category-button");
const buttonClear = document.querySelector(".clear-completed-button");
const itemsCountElement = document.getElementById("items-count");

• The task array can be updated as follows by adding the id and complete properties which will be false by default:

let todoList = [
  { id: 1, name: "Complete online JavaScript course", completed: false },
  { id: 2, name: "Jog around the park 3x", completed: false },
  { id: 3, name: "10 minutes meditation", completed: false },
  { id: 4, name: "Read for 1 hour", completed: false },
  { id: 5, name: "Pick up groceries", completed: false },
  { id: 6, name: "Complete Todo App on Frontend Mentor", completed: false },
];

• Create a variable to store the selected filter by default it will be "all": let currentFilter = "all";

• Add a function to render the list in the html:

1. This function receives a parameter called list that if passed this is used, otherwise the list todoList will be used.
2. In the variable html add the class "completed" to the container if task.completed is true using a ternary task.completed ? "completed" : "", also add a data-task-id="${task.id}" attribute, this will be used later for the update and delete actions and finally to the input the property checked is added if task.completed is true ${task.completed ? "checked" : ""}.

function renderTodoList(list) {
  const filteredList = list || todoList; // 1
  todoListContainer.innerHTML = "";

  filteredList.forEach((task) => {
    const html = `
      <div class="todo-list ${
        task.completed ? "completed" : ""
      }" data-task-id="${task.id}">
        <input name="completed" class="checkbox" type="checkbox" ${
          task.completed ? "checked" : ""
        }>
        <div class="todo-content">
          <p>${task.name}</p>
          <button class="delete-button">Delete</button>
        </div>
      </div>
    `; //2

    todoListContainer.innerHTML += html; //Insert the html
  });

  updateItemsLeftCounter(filteredList); // Update counter
}

• Now the functions to add, update, delete and filter:

1. Add task: Create an object with the data of the new task, as id in this case numbers are being used in order and to continue we use the todoList.length to obtain the number of elements of the tasks array and we add 1: id: todoList.length + 1, the name will be the value of the parameter name, and completed will be false, you add the new task to the array using todoList.push(newTask), render the list, reset the value of the input and finally the setTimeout is to uncheck the input a moment after the task is added

function addTask(name) {
  const newTask = {
    id: todoList.length + 1,
    name,
    completed: false,
  };

  todoList.push(newTask);
  renderTodoList();
  inputAddTask.value = "";

  setTimeout(() => {
    checkToAddTask.checked = false;
  }, 200);
}

1. Filter Task Function: This function receives the filter parameter and will be in charge of keeping the task lists updated in their respective category filters, first we create a copy of the tasks so as not to change the original array and avoid deleting certain tasks when switch categories, then use tasksCopy.filter to filter the categories: if filter === "all" return all tasks else if : filter === "completed" ? task.completed returns the tasks where task.completed equals true otherwise those with task.completed equal false, then stores the filter in the currentFilter variable and calls the renderTodoList(taskFiltered) function passing the filtered tasks as parameters.

function filterTask(filter) {
  const tasksCopy = [...todoList];
  const taskFiltered = tasksCopy.filter((task) =>
    filter === "all"
      ? task
      : filter === "completed"
      ? task.completed
      : !task.completed
  );

  currentFilter = filter;
  renderTodoList(taskFiltered);
}

1. Update task: This function receives the id of the task to update and to update the status of completed to said task we map the todoList, what this code does is that if the task.id is equal to the taskId passed as a parameter to the function task.id === taskId returns a copy of the task and updates the property completed ? { ...task, completed: !task.completed } this ...task is known as "spread operator" if you want to dig further into the topic, in the completed: ! task.completed, doing this !task.completed means it will change to the opposite if it was true the new value will be false and vice versa. Finally we call the function filterTask(currentFilter) passing the variable currentFilter as a parameter

function updateTask(taskId) {
  todoList = todoList.map((task) =>
    task.id === taskId ? { ...task, completed: !task.completed } : task
  );
  filterTask(currentFilter);
}

1. Delete and Clear completed: Both functions use the filter method, in the deleteTask function the filter method returns the tasks whose id is different from the id of the task to delete task.id !== taskId, and in the clearCompletedTasks function it returns the tasks whose value is completed is false

function deleteTask(taskId) {
  todoList = todoList.filter((task) => task.id !== taskId);
  filterTask(currentFilter);
}

function clearCompletedTasks() {
  todoList = todoList.filter((task) => !task.completed);
  filterTask(currentFilter);
}

1. Update Items Left: It is in charge of updating the number of elements in each category, the variable label is created, the result of which will be: if label is equal to "all" it returns "left", otherwise the name of the filter, then it is dynamically updates the quantity: Resulting in: eg: 5 items left, 2 items active, 3 items completed... this according to the selected category

function updateItemsLeftCounter(list) {
  const remainingItemCount = list.filter((task) => !task.completed).length;
  const label = currentFilter === "all" ? "left" : currentFilter;

  itemsCountElement.textContent = `${remainingItemCount} items ${label}`;
}

At the events listeners will have:

checkToAddTask.addEventListener("click", (e) => {
  const name = inputAddTask.value.trim(); //Value of the input without spaces
  if (name === "") { //If name is an empty string, we prevent the input from being checked
    e.preventDefault();
  } else { //Otherwise add the new task
    addTask(name);
  }
});

inputAddTask.addEventListener("keydown", (e) => {
  const name = inputAddTask.value.trim();
  if (e.key === "Enter" && name !== "") { // In the input if key Enter is pressed and name is not equal to an empty string add the new task
    checkToAddTask.checked = true;
    addTask(name);
  }
});

1. The clear button listener: buttonClear.addEventListener("click", clearCompletedTasks);

2. For the event listener of task kill buttons instead of selecting all buttons with "querySelectorAll" and using forEach, you can listen for the click event on the task container, for example:

   1. Here, event.target refers to the element that was clicked. .closest(".delete-button") finds the closest ancestor (parent) that has the class delete-button. This allows you to determine if the delete button was clicked, regardless of whether the click happened directly on the button or on an element internal to the button, the same goes for toggleCompleted.
   2. If deleteButton exists then we get the taskId which is passed as data-task-id="${task.id}" attribute to the task container in the renderTodoList function, the deleteButton.closest(".todo-list") part will access the parent element having the class "todo-list" and .dataset.taskId will get the data-task-id attribute and will calls the deleteTask function using the retrieved id as parameter.

todoListContainer.addEventListener("click", (event) => {
  // 1
  const deleteButton = event.target.closest(".delete-button");
  const toggleCompleted = event.target.closest(".checkbox");

  if (deleteButton) {
    // 2
    const taskId = parseInt(deleteButton.closest(".todo-list").dataset.taskId);
    deleteTask(taskId);
  }

  if (toggleCompleted) {
    const taskId = parseInt(
      toggleCompleted.closest(".todo-list").dataset.taskId
    );
    updateTask(taskId);
  }
});

And finally, the category filter function

categoryButtons.forEach((button) =>
  button.addEventListener("click", () => {
    //Find an element with the class "is-toggled"
    const toggled = document.querySelector(".is-toggled");

    // If there is, remove the class is toggled
    if (toggled) toggled.classList.remove("is-toggled");

    // And add it to the button pressed
    button.classList.add("is-toggled");

    // Get the name of the filter, remove the trailing spaces and change to lowercase
    const filter = button.textContent.trim().toLowerCase();

    // Call the filterTask function with the name of the filter
    filterTask(filter);
  })
);

In the CSS in the todo-list-container class you are defining a height of 390px, this will mean that when adding new tasks they will not be displayed since the height is fixed (always 390px), you can solve it by changing height by min-height this way it will be at least 390px and the container will be able to increase in size as you add new tasks, You can also add a background-color to the container since when deleting the tasks its background is transparent.

.todo-list-container {
  background-color: var(--color)
  min-height: 390px;
}

Here are some resources related to the code:

• Ternary operators
• JavaScript Ternary Operator
• JavaScript Spread Operator
• What is the spread operator in JavaScript?

Maybe the feedback is too long: D, but I hope it helps you and that it has helped you learn something new. Good luck!.

Hey, this looks really awesome. It can be very frustrating when you can't get things working quite right, but the HTML and CSS are on point and you have a lot of the functionality there.

I think a great resource for learning arrays and OOP (and where I learned them) is the 100devs course by Leon Noel on YouTube. You can probably skip the early classes because your HTML and CSS skill are absolutely on point.

Practice Arrays

Object Oriented Programming

You mentioned not understanding how your delete button works, let's take a look at it. Your current solution is concise, well formatted, and would probably be the way to do it in production for a company, but lets do a refactor along the way to make it easier to understand.

document.querySelectorAll('.delete-button')
    .forEach((deleteButton, index) => {
      deleteButton.addEventListener('click', () => {
        todoList.splice(index, 1);
        renderTodoList();
    });
  });

You start by calling document.querySelectorAll('.delete-button'). This goes through the document and finds ever item with the .delete-button class and adds them to an array. For readability, lets store that array in a variable instead

const deleteButtons = document.querySelectorAll('.delete-button');

deleteButtons
    .forEach((deleteButton, index) => {
      deleteButton.addEventListener('click', () => {
        todoList.splice(index, 1);
        renderTodoList();
    });
  });

Then you call array.forEach() method on the array. .forEach is a "higher order function," meaning it takes another function as an argument, which you're currently doing with an arrow function. Let's abstract that out into it's own function to make it more readable for us.

const deleteButtons = document.querySelectorAll('.delete-button');

  deleteButtons.forEach((deleteButton, index) => addDeleteListeners(deleteButton, index));

  function addDeleteListeners(deleteButton, index) {
    deleteButton.addEventListener('click', () => {
      todoList.splice(index, 1);
      renderTodoList();  
    })
  }

You do still have to use an arrow function to get the arguments but I think this makes things a little more readable for this. .forEach will loop through our array and perform a function on each item within it. In the arrow function of a .forEach the first argument is always the item itself. You can name it whatever you want, in this case it's deleteButton but you could name it element, el, e, zebra, fdsfjdsahfksldah etc. You can actually just have one argument if all you need is the item. So that would look like deleteButtons.forEach((deleteButton) => addDeleteListeners(deleteButton,)); We will, however, need the index as well. Since arrays are a numbered list of objects, index represents an item's position in the array. Indexes start at 0 so the first item's index will always be 0, not 1. We can actually access an individual item with the index using square brackets notation.

const deleteButtons = document.querySelectorAll('.delete-button');
console.log(deleteButtons[0]);
console.log(deleteButtons[1]);
console.log(deleteButtons[2]);

This will output each the first three buttons' HTML markup to the console. So index will be the second argument of .forEach. We can technically name it whatever we want, but generally just index or i is a good practice. Fun fact, you could add a third argument to this function, and that would be the array itself. Once again you can call it whatever you want. So deleteButtons.forEach((deleteButton, index, array) => addDeleteListeners(deleteButton, index, array)); We don't need to do that for this particular case however.

So onto the main part of this function.

deleteButton.addEventListener('click', () => {
      todoList.splice(index, 1);
      renderTodoList();  
    })

I won't explain event listeners as you already seem pretty comfortable with them, but note that since we are iterating over each element, it is adding an event listener to every object in the array.

Within the event listener you're using array.splice() on your todoList array. .splice is a function that removes an item from the array at a specific index. This is where our reference to the index comes in handy! Since every item in the todoList array has a delete button, todoList and deleteButtons will always be the same length, and because .querySelectorAll reads from top to bottom, they will always be in the same order! So .splice removes things from the array at a specific index, for that we'll just user our handy dandy index value. The second argument is how many items to remove. Of course for our purposes we only need to remove the item that is being deleted, so we just have that be 1. I hope this explanation helps!

I bet you could totally get the clear all button working! You very similarly use a .forEach with an if statement inside the function. in a statement like todoList.forEach((todo, index) => {//Your code here}), you can check if todo has the .completed class and splice it out if it does. Best of luck and keep up the awesome work!

Hi there! If you want to deepen your understanding of objects and arrays, I highly recommend learning platforms like FreeCodeCamp. They provide clear tutorials and challenges to help you master these concepts. Hope this helps!

Source: FreeCodeCamp