Welcome to the Treehouse Community

Want to collaborate on code errors? Have bugs you need feedback on? Looking for an extra set of eyes on your latest project? Get support with fellow developers, designers, and programmers of all backgrounds and skill levels here with the Treehouse Community! While you're at it, check out some resources Treehouse students have shared here.

Looking to learn something new?

Treehouse offers a seven day free trial for new students. Get access to thousands of hours of content and join thousands of Treehouse students and alumni in the community today.

Start your free trial

JavaScript DOM Scripting By Example Editing and Filtering Names Filter Invitees Who Have Not Responded

Posted by Siddharth Pandey
Siddharth Pandey
7,280 Points

Why does this code not work?

I feel like I have done everything right. However, this is definitely something missing, can someone explain why the checkbox for "Show Selected items" is not working and on the console whenever I press it, the console says "Uncaught TypeError: Cannot read property 'className' of undefined at HTMLDivElement.filter (script.js:21)" I do not understand what is wrong. Can someone please explain to me what is wrong and how to fix it.

Here is my code:

const form = document.querySelector('#registrar');
const input = form.querySelector('input');
const ul = document.querySelector('#invitedList');

const main = document.querySelector('.main');
const div = document.createElement('div');
const label = document.createElement('label');
const filter = document.createElement('input');

main.insertBefore(div, ul);
div.appendChild(label);
div.appendChild(filter);
filter.type = 'checkbox';
label.textContent = 'Show Selected Items';

div.addEventListener('click', function filter(e) {
 const unchecked = ul.children;
 if(e.target.tagName === 'INPUT') {
  for(let i = 0; i < ul.children.length; i += 1) {
    let li = ul[i];
   if (li.className === 'responded') {
    li.style.display = '';      
  } else {
    li.style.display = 'none';
  }
  }
 }
});
function createLI(text) {
  const li = document.createElement('li');
  const span = document.createElement('span');
  span.textContent = text;
  li.appendChild(span);
  const label = document.createElement('label');
  label.textContent ='Confirmed';
  const checkbox = document.createElement('input');
  checkbox.type = 'checkbox';  
  label.appendChild(checkbox);
  li.appendChild(label);

  const editButton = document.createElement('button');
  editButton.textContent = 'Edit';
  li.appendChild(editButton);

  const removeButton = document.createElement('button');
  removeButton.textContent = 'Remove';
  li.appendChild(removeButton);

  return li;
}


form.addEventListener('submit', function submit(name) {
  name.preventDefault();
  const text = input.value;
  input.value = '';
  const li = createLI(text);
  ul.appendChild(li);
});

ul.addEventListener('change', function styling(e) {
  const checkbox = e.target;
  const checked = e.target.checked;
  const listItem = checkbox.parentNode.parentNode;
  if (checked) {
    listItem.className = 'responded';
  } else {
    listItem.className = '';
  }
});

ul.addEventListener('click', function remove(e) {
const listItem = e.target.parentNode;
const ul = listItem.parentNode;
const button = e.target;
const li = button.parentNode;
 if (button.tagName == 'BUTTON') {
     if (button.textContent === 'Remove') {
      ul.removeChild(listItem);
   } else if (button.textContent === 'Edit') {
     const span = li.firstElementChild;
     const input = document.createElement('input');
     input.type = 'text';
     input.value = span.textContent;
     li.insertBefore(input, span);
     li.removeChild(span);
     button.textContent = 'Save';
   } else if (button.textContent === 'Save') {
     const input = li.firstElementChild;
     const span = document.createElement('span');
     span.textContent = input.value; 
     li.insertBefore(span, input);
     li.removeChild(input);
     button.textContent = 'Edit';
   }
 }
});

Thanks For Helping! Sid

1 Answer

KRIS NIKOLAISEN
KRIS NIKOLAISEN
54,967 Points
KRIS NIKOLAISEN
KRIS NIKOLAISEN
54,967 Points

li is list item. So in your for loop in div.addEventListener perhaps you meant:

let li = ul.children[i];
Siddharth Pandey
Siddharth Pandey
7,280 Points

I changed that but and some other things but I still get the syntax error "Cannot read property 'className' of undefined[.]" Can you please explain what is not working?

Here is the revised code:

const form = document.querySelector('#registrar');
const input = form.querySelector('input');
const ul = document.querySelector('#invitedList');

const main = document.querySelector('.main');
const div = document.createElement('div');
const label = document.createElement('label');
const filter = document.createElement('input');

main.insertBefore(div, ul);
div.appendChild(label);
div.appendChild(filter);
filter.type = 'checkbox';
label.textContent = 'Show Selected Items';

div.addEventListener('change', function filter(e) {
 const unchecked = ul.children;
 if(e.target.tagName === 'INPUT') {
  for(let i = 0; i < ul.children.length; i += 1) {
    let li = ul[i];
    console.log(ul.children);
   if (li.className =='responded') {
    li.style.display = '';      
  } else {
    li.style.display = 'none';
  }
  }
 }
});
function createLI(text) {
  const li = document.createElement('li');
  const span = document.createElement('span');
  span.textContent = text;
  li.appendChild(span);
  const label = document.createElement('label');
  label.textContent ='Confirmed';
  const checkbox = document.createElement('input');
  checkbox.type = 'checkbox';  
  label.appendChild(checkbox);
  li.appendChild(label);

  const editButton = document.createElement('button');
  editButton.textContent = 'Edit';
  li.appendChild(editButton);

  const removeButton = document.createElement('button');
  removeButton.textContent = 'Remove';
  li.appendChild(removeButton);

  return li;
}


form.addEventListener('submit', function submit(name) {
  name.preventDefault();
  const text = input.value;
  input.value = '';
  const li = createLI(text);
  ul.appendChild(li);
});

ul.addEventListener('change', function styling(e) {
  const checkbox = e.target;
  const checked = e.target.checked;
  const listItem = checkbox.parentNode.parentNode;
  if (checked) {
    listItem.className = 'responded';
  } else {
    listItem.className = '';
  }
});

ul.addEventListener('click', function remove(e) {
const listItem = e.target.parentNode;
const ul = listItem.parentNode;
const button = e.target;
const li = button.parentNode;
 if (button.tagName == 'BUTTON') {
     if (button.textContent === 'Remove') {
      ul.removeChild(listItem);
   } else if (button.textContent === 'Edit') {
     const span = li.firstElementChild;
     const input = document.createElement('input');
     input.type = 'text';
     input.value = span.textContent;
     li.insertBefore(input, span);
     li.removeChild(span);
     button.textContent = 'Save';
   } else if (button.textContent === 'Save') {
     const input = li.firstElementChild;
     const span = document.createElement('span');
     span.textContent = input.value; 
     li.insertBefore(span, input);
     li.removeChild(input);
     button.textContent = 'Edit';
   }
 }
});