Welcome to the Treehouse Community

The Treehouse Community is a meeting place for developers, designers, and programmers of all backgrounds and skill levels to get support. Collaborate here on code errors or bugs that you need feedback on, or asking for an extra set of eyes on your latest project. Join thousands of Treehouse students and alumni in the community today. (Note: Only Treehouse students can comment or ask questions, but non-students are welcome to browse our conversations.)

Looking to learn something new?

Treehouse offers a seven day free trial for new students. Get access to thousands of hours of content and a supportive community. Start your free trial today.

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

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

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

let li = ul.children[i];

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';
   }
 }
});