如何从本地存储 onclick 中删除数组中的项目

Question

我有以下代码。每次用户单击“添加到购物车”按钮时，它都会将信息存储在本地存储中：

let addCartItemButtons = document.getElementsByClassName('product-description-add')
for (let i = 0; i < addCartItemButtons.length; i++){
    let button = addCartItemButtons[i]
    button.addEventListener('click', addProduct)
} 

function addProduct(event) {
    let buttonClicked = event.target
    let getTitle = buttonClicked.parentElement.parentElement.parentElement.querySelector('.product-title').innerText
    let getImage = buttonClicked.parentElement.parentElement.parentElement.querySelector('.product-header img').src
    let getColor = buttonClicked.parentElement.parentElement.querySelector('.product-description-text li span').innerText
    let getSize = buttonClicked.parentElement.parentElement.querySelector('.product-description-text li select').value
    let getPrice = buttonClicked.parentElement.parentElement.querySelector('.product-description-price').innerText
    let getSpan = buttonClicked.parentElement.parentElement.querySelector('li span').getAttribute('id')

    let oldItems = JSON.parse(localStorage.getItem('newProduct')) || [];
    let newItem = {
        'title': getTitle,
        'image': getImage,
        'color': getColor,
        'size': getSize,
        'price': getPrice,
        'spanid': getSpan,
    };
    
    oldItems.push(newItem);
    localStorage.setItem('newProduct', JSON.stringify(oldItems));
}

然后，我有一个代码允许我通过创建 div 并显示信息来显示用户在本地存储的数据：

let cartProducts = JSON.parse(localStorage.getItem("newProduct"))
for(let i = 0; i < cartProducts.length; i++){
    let newCartProduct = document.createElement('div')
    newCartProduct.classList.add('product')
    newCartProduct.classList.add('cart')
    const image = cartProducts[i].image
    const title = cartProducts[i].title
    const spanid = cartProducts[i].spanid
    const color = cartProducts[i].color
    const size = cartProducts[i].size
    const price = cartProducts[i].price
    let newCartProductContent = `
    <div class="product-header cart"><img src="${image}" alt="" /></div>
        <div class="product-content">
            <h3 class="product-title" id="product-title">
            ${title} 
            </h3>
            <div class="product-description">
                <ul class="product-description-text cart">
                    <li>Color: <span id="${spanid}">${color} </span></li>
                    <li>Size: ${size} </li>
                    <li>Quantity: <input type="number" class="product-description-quantity" min="1" placeholder="2" value="2"></li>
                </ul>
                <p class="product-description-price" id="price1">
                ${price} 
                </p>
                **<a href="#" class="product-description-add cart-remove">Remove<i class="fas fa-trash"></i></a>**
            </div>
        </div>`
    newCartProduct.innerHTML = newCartProductContent
    let cartItems = document.getElementsByClassName('products_container_first-row')[0]
    cartItems.append(newCartProduct)
}

所以我现在需要做的是创建一个函数，允许我删除本地存储上的相同数据，每次用户点击“删除”按钮（在上面的代码中是在开头和结尾都有 ** ** 的行），但我不知道该怎么做。有任何想法吗？谢谢！

更新：我已经看到这段代码，但我得到 -1 作为每个元素的索引：

let addCartItemButtons = document.getElementsByClassName('product-description-add')
for (let i = 0; i < addCartItemButtons.length; i++){
    let button = addCartItemButtons[i]
    button.addEventListener('click', function(event){
        let buttonClicked = event.target
        let getTitle = buttonClicked.parentElement.parentElement.parentElement.querySelector('.product-title').innerText
        let getImage = buttonClicked.parentElement.parentElement.parentElement.querySelector('.product-header img').src
        console.log(getImage)
        let getColor = buttonClicked.parentElement.parentElement.querySelector('.product-description-text li span').innerText
        let getSize = buttonClicked.parentElement.parentElement.querySelector('.product-description-text li select').value
        let getPrice = buttonClicked.parentElement.parentElement.querySelector('.product-description-price').innerText
        let getSpan = buttonClicked.parentElement.parentElement.querySelector('li span').getAttribute('id')
        console.log(getSpan)
    
        let oldItems = JSON.parse(localStorage.getItem('newProduct')) || [];
        let newItem = {
            'id': i+1,
            'title': getTitle,
            'image': getImage,
            'color': getColor,
            'size': getSize,
            'price': getPrice,
            'spanid': getSpan,
        };
        
        oldItems.push(newItem);
        localStorage.setItem('newProduct', JSON.stringify(oldItems));
    })
} 

let cartProducts = JSON.parse(localStorage.getItem("newProduct"));
for(let i = 0; i < cartProducts.length; i++){
    let newCartProduct = document.createElement('div')
    newCartProduct.classList.add('product')
    newCartProduct.classList.add('cart')
    console.log(newCartProduct)
    const id = cartProducts[i].id
    const image = cartProducts[i].image
    const title = cartProducts[i].title
    const spanid = cartProducts[i].spanid
    const color = cartProducts[i].color
    const size = cartProducts[i].size
    const price = cartProducts[i].price
    let newCartProductContent = `
    <div class="product-header cart" id="${id}"><img src="${image}" alt="" /></div>
        <div class="product-content">
            <h3 class="product-title" id="product-title">
            ${title} 
            </h3>
            <div class="product-description">
                <ul class="product-description-text cart">
                    <li>Color: <span id="${spanid}">${color} </span></li>
                    <li>Size: ${size} </li>
                    <li>Quantity: <input type="number" class="product-description-quantity" min="1" placeholder="2" value="2"></li>
                </ul>
                <p class="product-description-price">
                ${price} 
                </p>
                <a href="#" onclick="lsdel(\'newProduct\',\'+cartProducts[i].id+\');" class="product-description-add cart-remove">Remove<i class="fas fa-trash"></i></a>
            </div>
        </div>`
    newCartProduct.innerHTML = newCartProductContent
    let cartItems = document.getElementsByClassName('products_container_first-row')[0]
    cartItems.append(newCartProduct)
}
function lsdel(storage_name, value){
    if (localStorage.getItem(storage_name) === null) { 
    } else {        
        var ls_data = JSON.parse(localStorage.getItem(storage_name));
        var index   = ls_data.indexOf(value);
        console.log("selected index:"+index);
        if(index == -1){
        // if not matched selected index    
        } else {
            // is matched, remove...
            ls_data.splice(index, 1);
            localStorage.setItem(storage_name, JSON.stringify(ls_data));
            console.log(ls_data);  
        }
    }
}

Answer 1

value是一个元素的ID，但是ls_data是一个对象数组，不是ID。所以ls_data.indexOf(value)不会在数组中找到对象。即使 value 是一个对象，这也行不通，因为对象相等性是基于内存中的相同对象，而不是比较内容。

您需要使用findIndex来匹配数组元素的id属性。

function lsdel(storage_name, value) {
  if (localStorage.getItem(storage_name) === null) {} else {
    var ls_data = JSON.parse(localStorage.getItem(storage_name));
    var index = ls_data.findIndex(({id}) => id == value);
    console.log("selected index:" + index);
    if (index == -1) {
      // if not matched selected index    
    } else {
      // is matched, remove...
      ls_data.splice(index, 1);
      localStorage.setItem(storage_name, JSON.stringify(ls_data));
      console.log(ls_data);
    }
  }
}

如何从本地存储 onclick 中删除数组中的项目

How to delete an item from an array from localstorage onclick

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local-storage