我正在制作一個簡單的待辦事項清單。您從輸入提交專案，然后他們轉到待辦事項部分。當您單擊它們時，它們會轉到“完成”部分。當您再次單擊它們時，它們將永遠消失。一切正常。
但我意識到 doneItens 陣列的長度一直在增長，我想對其進行優化。所以我想出了這行代碼
doneItens.splice(i, 1);
它位于 onclick 事件中，您可以在 deleteDone 函式內的代碼中看到該事件。
但是，這給出了錯誤，
Error:{ "message": "Uncaught TypeError: doneItens.splice is not a function"
如果我把它放在 onclick 事件的外面和下面，它也不起作用。我該怎么做？
var input = document.getElementById('play');
var toDo = document.getElementsByTagName('ol')[0];
var done = document.getElementById('done');
function handleSubmit(event) {
event.preventDefault();
const newItem = document.createElement('li');
newItem.setAttribute('class', 'item');
newItem.append(input.value);
toDo.append(newItem);
input.value='';
deleteItem();
}
function deleteItem() {
const toBeDone = document.getElementsByClassName('item');
for(let i = 0; i < toBeDone.length; i ) {
toBeDone[i].onclick = () => {
appendItemDone(toBeDone[i]);
toBeDone[i].style.display = 'none';
deleteDone();
}
}
}
function appendItemDone(item) {
const newDone = document.createElement('li');
newDone.setAttribute('class', 'feito')
newDone.append(item.innerText);
done.append(newDone);
}
function deleteDone() {
const doneItens = document.getElementsByClassName('feito');
console.log('done length', doneItens.length)
for (let i = 0; i < doneItens.length; i ) {
doneItens[i].onclick = () => {
doneItens[i].style.display = 'none';
doneItens.splice(i, 1);
}
}
}<div id='flex'>
<form class='form' onsubmit='handleSubmit(event)'>
<input placeholder='New item' type='text' id='play'>
<button>Send</button>
</form>
<div id='left'>
<h1 id='todo' >To-do:</h1>
<p class='instruction'><i>(Click over to mark as done)</i></p>
<ol id='here'></ol>
</div>
<div id='right'>
<h1>Done:</h1>
<p class='instruction'><i>(Click over to delete it)</i></p>
<p id='placeholder'></p>
<ol id='done'></ol>
</div>
</div>uj5u.com熱心網友回復：
您將要使用splice，然后done通過添加拼接陣列中的所有元素來“重繪 ”元素，而不是使用隱藏。
我已經評論了我所做更改的代碼以及原因
var input = document.getElementById('play');
var toDo = document.getElementsByTagName('ol')[0];
var done = document.getElementById('done');
function handleSubmit(event) {
event.preventDefault();
const newItem = document.createElement('li');
newItem.setAttribute('class', 'item');
newItem.append(input.value);
toDo.append(newItem);
input.value='';
deleteItem();
}
function deleteItem() {
const toBeDone = document.getElementsByClassName('item');
for(let i = 0; i < toBeDone.length; i ) {
toBeDone[i].onclick = () => {
appendItemDone(toBeDone[i].cloneNode(true));
toBeDone[i].style.display = 'none';
deleteDone();
}
}
}
function appendItemDone(item) {
const newDone = document.createElement('li');
newDone.setAttribute('class', 'feito')
newDone.append(item.innerText);
done.append(newDone);
}
function deleteDone() {
var doneItens = document.getElementsByClassName('feito');
for (let i = 0; i < doneItens.length; i ) {
doneItens[i].onclick = () => {
var splicedArray = spliceFromArray(doneItens,doneItens[i]);// NEW BIT -CALL NEW SPLICE FUNCTION
done.innerHTML=""; // NEW BIT - SET OVERALL DONE TO BLANK ON DELETE
for(var index in splicedArray){// NEW BIT - fOR EACH RETURNED ELEMENT IN THE SPLICE, ADD IT TO THE OVERALL DONE ELEMENT
done.appendChild(splicedArray[index]);
}
}
}
}
function spliceFromArray(arrayInput,element){// NEW BIT - SPLICE FUNCTION THAT RETURNS SPLICED ARRAY
var array = Array.from(arrayInput);
var index = array.indexOf(element);
if(index!=-1){
if(array.length==1 && index == 0){
array = [];
}
else{
array.splice(index,1);
}
}
return array;
}<div id='flex'>
<form class='form' onsubmit='handleSubmit(event)'>
<input placeholder='New item' type='text' id='play'>
<button>Send</button>
</form>
<div id='left'>
<h1 id='todo' >To-do:</h1>
<p class='instruction'><i>(Click over to mark as done)</i></p>
<ol id='here'></ol>
</div>
<div id='right'>
<h1>Done:</h1>
<p class='instruction'><i>(Click over to delete it)</i></p>
<p id='placeholder'></p>
<ol id='done'></ol>
</div>
</div>uj5u.com熱心網友回復：
通過使用 JavaScript DOM API，例如Node.removeChild()、Element.remove()和Node.parentNode，您的任務可以通過以下代碼解決：
const input = document.getElementById('play');
const todo = document.getElementById('todo');
const done = document.getElementById('done');
function handleSubmit(event) {
event.preventDefault();
// create new "todo" item
const newTodo = document.createElement('li');
newTodo.textContent = input.value;
todo.append(newTodo);
// clean the input field
input.value = '';
// listen to "click" event on the created item to move it to "done" section
newTodo.addEventListener('click', moveToDone);
}
function moveToDone(event) {
// remove "click"-listener to prevent event listener leaks
event.target.removeEventListener('click', moveToDone);
// move clicked todo-element to "done" section
const newDone = event.target.parentNode.removeChild(event.target);
done.append(newDone);
// listen to "click" event on the moved item to then completely delete it
newDone.addEventListener('click', removeFromDone);
debugElementsLeak();
}
function removeFromDone(event) {
// remove "click"-listener to prevent event listener leaks
event.target.removeEventListener('click', removeFromDone);
// complete remove clicked element from the DOM
event.target.remove();
debugElementsLeak();
}
function debugElementsLeak() {
const todoCount = document.getElementById('todo').childElementCount;
const doneCount = document.getElementById('done').childElementCount;
console.log({ todoCount, doneCount });
}<div id="flex">
<form class="form" onsubmit="handleSubmit(event)">
<input placeholder="New item" type="text" id="play">
<button>Add item</button>
</form>
<div id="left">
<h1>To-do:</h1>
<p class="instruction"><em>(Click over to mark as done)</em></p>
<ol id="todo"></ol>
</div>
<div id="right">
<h1>Done:</h1>
<p class="instruction"><em>(Click over to delete it)</em></p>
<p id="placeholder"></p>
<ol id="done"></ol>
</div>
</div>轉載請註明出處，本文鏈接：https://www.uj5u.com/gongcheng/413749.html
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