JavaScript Course | Task Tracker Project

Previous article: JavaScript Course | Objects in JavaScript

Project Introduction
In this final article of this course we will learn how to make a simple javascript application where we can add tasks, delete tasks and edit them too. Pure(Vanilla) JavaScript has been used and we will also make use of DOM manipulation a lot so one of the main prerequisites is HTML | DOM.
Project Structure

index.html
styles.css
list.js

index.html

<!DOCTYPE html> 
<html> 
<head> 
  <title>Task Tracker</title> 
  <link rel="stylesheet" href="styles.css" type="text/css" 
    media="screen" charset="utf-8"> 
</head> 
  
<body> 
  <div class="container"> 
    <p> 
      <label for="new-task" class="middle">Add Task</label> 
    <input id="new-task" type="text"><button>Add Task</button> 
    </p> 
  
    <h3 class="middle">Todo</h3> 
    <ul id="incomplete-tasks"> 
    </ul> 
  
    <h3 class="middle">Completed Tasks</h3> 
    <ul id="completed-tasks"> 
    </ul> 
  </div> 
  
  <script type="text/javascript" src="list.js"></script> 
  
</body> 
  
</html> 

Explanation:
The above HTML code contains simple list tags and one text field which we will populate with text when we add, delete tasks. Certain classes are assigned which we make use of while getting that particular element by DOM or by styling it inside the styles.css file. All the above content is inside a div with class ‘container’ that has its own styling and attributes.

styles.css

/* Basic Style */
body { 
  background: #ecf0f1; 
  color: #333; 
  font-family: Lato, sans-serif; 
} 
  
.container { 
  display: block; 
  width: 500px; 
  margin: 50px auto 0; 
} 
  
ul { 
  margin: 0; 
  padding: 0; 
} 
  
li * { 
  float: left; 
} 
  
li, 
h3 { 
  clear: both; 
  list-style: none; 
} 
  
input, 
button { 
  outline: none; 
} 
  
button { 
  background: none; 
  border: 0px; 
  color: #888; 
  font-size: 15px; 
  width: 100px; 
  margin: 10px 0 0; 
  font-family: Lato, sans-serif; 
  cursor: pointer; 
} 
  
button:hover { 
  color: #333; 
} 
  
/* Heading */
h3, 
label[for='new-task'] { 
  color: #333; 
  font-weight: 700; 
  font-size: 15px; 
  border-bottom: 2px solid #333; 
  padding: 30px 0 10px; 
  margin: 0; 
  text-transform: uppercase; 
} 
  
input[type="text"] { 
  margin: 0; 
  font-size: 18px; 
  line-height: 18px; 
  height: 18px; 
  padding: 10px; 
  border: 1px solid #ddd; 
  background: #fff; 
  border-radius: 6px; 
  font-family: Lato, sans-serif; 
  color: #888; 
} 
  
input[type="text"]:focus { 
  color: #333; 
} 
  
.middle { 
  text-align: center; 
} 
  
  
/* New Task */
label[for='new-task'] { 
  display: block; 
  margin: 0 0 20px; 
} 
  
input#new-task { 
  float: right; 
  width: 318px; 
} 
  
p>button:hover { 
  color: #0FC57C; 
} 
  
/* Task list */
li { 
  overflow: hidden; 
  padding: 20px 0; 
  border-bottom: 1px solid #eee; 
} 
  
li>input[type="checkbox"] { 
  margin: 0 10px; 
  position: relative; 
  top: 15px; 
} 
  
li>label { 
  font-size: 18px; 
  line-height: 40px; 
  width: 237px; 
  padding: 0 0 0 11px; 
} 
  
li>input[type="text"] { 
  width: 226px; 
} 
  
li>.delete:hover { 
  color: #CF2323; 
} 
  
/* Completed */
#completed-tasks label { 
  text-decoration: line-through; 
  color: #888; 
} 
  
/* Edit Task */
ul li input[type=text] { 
  display: none; 
} 
  
ul li.editMode input[type=text] { 
  display: block; 
} 
  
ul li.editMode label { 
  display: none; 
} 

Note: The above HTML and CSS files are for the presentation part mainly.

list.js

// Add a new task. 
let taskInput = document.getElementById("new-task");  
  
// first button 
let addButton = document.getElementsByTagName("button")[0];  
  
// ul of #incomplete-tasks 
let incompleteTaskHolder = document.getElementById("incomplete-tasks");  
  
// completed-tasks 
let completedTasksHolder = document.getElementById("completed-tasks");  
   
/*---- Part 1 ----*/
// function to create new task item 
let createNewTaskElement = function (taskString) { 
   
    let listItem = document.createElement("li"); 
   
    // input (checkbox) 
    let checkBox = document.createElement("input"); // checkbox 
    // label 
    let label = document.createElement("label"); // label 
    // input (text) 
    let editInput = document.createElement("input"); // text 
    // button.edit 
    let editButton = document.createElement("button"); // edit button 
   
    // button.delete 
    let deleteButton = document.createElement("button"); // delete button 
   
    label.innerText = taskString; 
   
    // Each elements, needs appending 
    checkBox.type = "checkbox"; 
    editInput.type = "text"; 
   
  
    // innerText encodes special characters, HTML does not. 
    editButton.innerText = "Edit";      
    editButton.className = "edit"; 
    deleteButton.innerText = "Delete"; 
    deleteButton.className = "delete"; 
   
    // and appending. 
    listItem.appendChild(checkBox); 
    listItem.appendChild(label); 
    listItem.appendChild(editInput); 
    listItem.appendChild(editButton); 
    listItem.appendChild(deleteButton); 
    return listItem; 
} 
/*---- Part 2 ----*/
let addTask = function () { 
    console.log("Add Task..."); 
   
    let listItem = createNewTaskElement(taskInput.value); 
   
    if (taskInput.value == "") { 
        return; 
    } 
   
    // Append listItem to incompleteTaskHolder 
    incompleteTaskHolder.appendChild(listItem); 
    bindTaskEvents(listItem, taskCompleted); 
   
    taskInput.value = ""; 
   
} 
   
/*---- Part 3 ----*/
let editTask = function () { 
    console.log("Edit Task..."); 
    console.log("Change 'edit' to 'save'"); 
   
   
    let listItem = this.parentNode; 
   
    let editInput = listItem.querySelector('input[type=text]'); 
    let label = listItem.querySelector("label"); 
    let containsClass = listItem.classList.contains("editMode"); 
    // If class of the parent is .editmode 
    if (containsClass) { 
        label.innerText = editInput.value; 
    } else { 
        editInput.value = label.innerText; 
    } 
    listItem.classList.toggle("editMode"); 
} 
   
/*---- Part 4 ----*/
let deleteTask = function () { 
    console.log("Delete Task..."); 
   
    let listItem = this.parentNode; 
    let ul = listItem.parentNode; 
    // Remove the parent list item from the ul. 
    ul.removeChild(listItem); 
   
} 
   
/*---- Part 5 ----*/
   
let taskCompleted = function () { 
    console.log("Complete Task..."); 
   
    // Append the task list item to the #completed-tasks 
    let listItem = this.parentNode; 
    completedTasksHolder.appendChild(listItem); 
    bindTaskEvents(listItem, taskIncomplete); 
   
} 
   
/*---- Part 6 ----*/
let taskIncomplete = function () { 
    console.log("Incomplete Task..."); 
    // Mark task as incomplete. 
    let listItem = this.parentNode; 
    incompleteTaskHolder.appendChild(listItem); 
    bindTaskEvents(listItem, taskCompleted); 
} 
   
/*---- Part 7 ----*/
addButton.onclick = addTask; 
addButton.addEventListener("click", addTask); 
   
let bindTaskEvents = function (taskListItem, checkBoxEventHandler) { 
    console.log("bind list item events"); 
    // select ListItems children 
    let checkBox = taskListItem.querySelector("input[type=checkbox]"); 
    let editButton = taskListItem.querySelector("button.edit"); 
    let deleteButton = taskListItem.querySelector("button.delete"); 
   
   
    // Bind editTask to edit button. 
    editButton.onclick = editTask; 
    // Bind deleteTask to delete button. 
    deleteButton.onclick = deleteTask; 
    // Bind taskCompleted to checkBoxEventHandler. 
    checkBox.onchange = checkBoxEventHandler; 
} 
   
/*---- Part 8 ----*/
// cycle over incompleteTaskHolder ul list items 
// for each list item 
for (let i = 0; i < incompleteTaskHolder.children.length; i++) { 
   
    // bind events to list items chldren(tasksCompleted) 
    bindTaskEvents(incompleteTaskHolder.children[i], taskCompleted); 
} 
   
// cycle over completedTasksHolder ul list items 
for (let i = 0; i < completedTasksHolder.children.length; i++) { 
    // bind events to list items chldren(tasksIncompleted) 
    bindTaskEvents(completedTasksHolder.children[i], taskIncomplete); 
} 

Explanation

Part 1
- The way this function wrorks is that it takes the ‘inputString’ i.e the text that we pass inside the HTML text field as a task and then it creates several elements using DOM properties and append them specific classes. After appending we insert all the elements inside the list as listItems.
Part 2
- This addTask function is called when we click the button ‘addButton'(line 115) and then inside it we create a listItem with the value the user entered and then check the value, as it must not be an empty string then we simply add the above value inside the ‘inputTaskHolder’ and finally setting the value inside it as an empty string before calling the ‘bindFunction’.
Part 3
- This code function is used to edit an existing task and we do so keeping track of the parent node and then a simple if-else check that whether the ‘editMode’ button is clicked or not, if clicked then simply assign the value of the label innerText to value inside the editInput, if not then vice versa. Then after editing, we toggle the value of the ‘editMode’ as we have edited.
Part 4
- In this part we delete a task and the way we do it by making use of the parent node of the current node and then storing the parent of the parent node and then simply deleting the child of this node.
Part 5
- In this function we mark the task as complete by simply appending the child of the parent node inside the completeTaskHolder element and then calling the bindFunction.
Part 6
- In this function we mark the task as incomplete by simply appending the child of the parent node inside the inCompleteTaskHolder element and then calling the bindFunction.
Part 7
- In this part we call the BindFunction where we respond to the several user interaction activities and make several buttons work.
Part 8
- In this final section we iterate over several parts binding childrens with the help of for loop inside the incomplete and complete TaskHolder element.

Output:(Before adding any task)

Output:(After adding task)

Output:(After Completing the task)

Next article: JavaScript Course | Practice Quiz-3

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