To do list clear button-CodePudding

im creating to-do list without any tutorial and i stucked when i tried to code clear button. I have a problem because this code removing only half of 'li' items in my list. I checked length of document.querySelectorAll('li) and it return correct value of list length , and i think in each loop execution i delete first element because document.querySelector('li) return only first element. Could you help me? And another question : Is somewhere in web program that can i see step by step exection of my code with DOM? I found few sites but there i can only debug code without html and css.

There is my code:

let clear = document.querySelector('.clear');
let input = document.querySelector('.input');
let submit = document.querySelector('.submit');
let list = document.querySelector('.list');

submit.addEventListener('click', function() {

  const el = document.createElement('li');

  list.appendChild(el);

  let items = document.querySelectorAll('li');

  for (i = 0; i < items.length; i  ) {
    items[items.length - 1].textContent = input.value;

  }
});

clear.addEventListener('click', function() {
  console.log(document.querySelectorAll('li').length);

  for (i = 0; i < document.querySelectorAll('li').length; i  )
    list.removeChild(document.querySelector('li'));
  console.log(list);
});

* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

body {
  display: flex;
  justify-content: flex-start;
  align-items: center;
  flex-direction: column;
  max-height: 100vh;
  max-width: 90vw;
}

h1 {
  text-align: center;
}

.wrap {
  padding: 50px;
  border: 2px solid black;
  border-radius: 20%;
  background-color: red;
}

.list {
  width: 100%;
  margin-left: 100px;
  font-size: 2rem;
  font-weight: bold;
}

<!DOCTYPE html>
<html lang="en">

<head>
  <meta charset="UTF-8" />
  <meta http-equiv="X-UA-Compatible" content="IE=edge" />
  <meta name="viewport" content="width=device-width, initial-scale=1.0" />
  <title>Document</title>
  <link rel="stylesheet" href="style.css" />
</head>

<body>
  <div >
    <h1>To do list</h1>
    <input type="text" placeholder="Add an item!"  />
    <button >Submit</button>
    <button >Clear List</button>
  </div>
  <ol ></ol>
  <script src="script.js"></script>
</body>

</html>

CodePudding user response：

In your case, your loop was calculating its length each time of the loop while i was still incrementing

I you had two elements, it would have deleted the first item, then at the second loop, the list would have a length of 1 and i would be equals to 1 so the loop would break

You can use a for of loop instead of a for i loop and remove the child by reference

clear.addEventListener('click', function() {
  const childs = document.querySelectorAll('li')
  for (const child of childs){
    list.removeChild(child)
  }
});

Note : this can also be done using a for i loop if you instantiate the list

clear.addEventListener('click', function() {
  const childs = document.querySelectorAll('li')
  for (let i = 0; i < childs.length; i  ){
    list.removeChild(childs[i])
  }
});

CodePudding user response：

I invent a new way to solve it

clear.addEventListener('click', function () {
  for (i = 0; i < document.querySelectorAll('li').length   i; i  )
    list.removeChild(document.querySelector('li'));
  console.log(list);
});

In each iteration I add 'i' . So i update length