每 3 个元素包裹一个父元素

问题描述 投票：0回答：3

我只是想用一类搜索音频围绕每 3 个 div 包装一个 div w 类幻灯片。

我遇到的一个错误是说 elem.parentElement 未定义...

所以部分效果很好...

const audioBlocks = document.querySelectorAll('.search-audio');
const slider = document.querySelector('.slider');
const audioBlockArr = Array.from(audioBlocks);

function groupBlocks(arr, len) {

    let groups = [],
        i = 0,
        n = arr.length;
  
    while (i < n) {
      groups.push(arr.slice(i, i += len));
    }
  
    return groups;
  }

newArr = [...groupBlocks(audioBlockArr, 3)];

问题就在这里——用一个 div 包裹新的分组元素数组。

let wrap = (array) => {
  
  array.forEach((elem) => {
    let div = document.createElement('div');
    div.classList.add('slide');
    div.innerHTML = '';

    elem.parentElement.insertBefore(div, elem);
    div.appendChild(elem);
  });
}

wrap(newArr);

完整代码：

const audioBlocks = document.querySelectorAll('.search-audio');
const slider = document.querySelector('.slider');
const audioBlockArr = Array.from(audioBlocks);

function groupBlocks(arr, len) {

  let groups = [],
    i = 0,
    n = arr.length;

  while (i < n) {
    groups.push(arr.slice(i, i += len));
  }

  return groups;
}

newArr = [...groupBlocks(audioBlockArr, 3)];

let wrap = (array) => {
  array.forEach((elem) => {
    let div = document.createElement('div');
    div.classList.add('slide');
    div.innerHTML = '';

    elem.parentElement.insertBefore(div, elem);
    div.appendChild(elem);
  });
}

wrap(newArr);
body {
  font-family: system-ui;
  background: #f06d06;
  color: white;
  text-align: center;
}

.search-audio {
  height: 12rem;
  width: 12rem;
  background: rgb(255, 153, 0);
  margin: .5rem;
  display: inline-block;
}

.slide {
  background-color: #555;
}
<body>
  <div class="slider">
    <div class="search-audio 1"></div>
    <div class="search-audio 2"></div>
    <div class="search-audio 3"></div>
    <div class="search-audio 4"></div>
    <div class="search-audio 5"></div>
    <div class="search-audio 6"></div>
    <div class="search-audio 7"></div>
    <div class="search-audio 8"></div>
    <div class="search-audio 9"></div>
    <div class="search-audio 10"></div>
    <div class="search-audio 11"></div>
    <div class="search-audio 12"></div>
    <div class="search-audio 13"></div>
    <div class="search-audio 14"></div>
    <div class="search-audio 15"></div>
    <div class="search-audio 16"></div>
    <div class="search-audio 17"></div>
    <div class="search-audio 18"></div>
    <div class="search-audio 19"></div>
    <div class="search-audio 20"></div>
  </div>
</body>

</html>

javascript arrays foreach parent-child
3个回答
1
投票

问题是

elem
不是单个元素，它是由
groupBlocks()
创建的3个元素的数组。所以没有
elem.parentElement
.

使用

elem[0].parentElement
获取所有元素的公共父元素。然后遍历它们以将每个元素附加到新的 div。

我在下面的代码中将 

elem
重命名为 
group
，以更正确地匹配它包含的内容。

const audioBlocks = document.querySelectorAll('.search-audio');
const slider = document.querySelector('.slider');
const audioBlockArr = Array.from(audioBlocks);

function groupBlocks(arr, len) {

  let groups = [],
    i = 0,
    n = arr.length;

  while (i < n) {
    groups.push(arr.slice(i, i += len));
  }

  return groups;
}

newArr = [...groupBlocks(audioBlockArr, 3)];

let wrap = (array) => {
  array.forEach((group) => {
    let div = document.createElement('div');
    div.classList.add('slide');
    div.innerHTML = '';

    group[0].parentElement.insertBefore(div, group[0]);
    group.forEach(elem => div.appendChild(elem));
  });
}

wrap(newArr);
body {
  font-family: system-ui;
  background: #f06d06;
  color: white;
  text-align: center;
}

.search-audio {
  height: 12rem;
  width: 12rem;
  background: rgb(255, 153, 0);
  margin: .5rem;
  display: inline-block;
}

.slide {
  background-color: #555;
}
<body>
  <div class="slider">
    <div class="search-audio 1"></div>
    <div class="search-audio 2"></div>
    <div class="search-audio 3"></div>
    <div class="search-audio 4"></div>
    <div class="search-audio 5"></div>
    <div class="search-audio 6"></div>
    <div class="search-audio 7"></div>
    <div class="search-audio 8"></div>
    <div class="search-audio 9"></div>
    <div class="search-audio 10"></div>
    <div class="search-audio 11"></div>
    <div class="search-audio 12"></div>
    <div class="search-audio 13"></div>
    <div class="search-audio 14"></div>
    <div class="search-audio 15"></div>
    <div class="search-audio 16"></div>
    <div class="search-audio 17"></div>
    <div class="search-audio 18"></div>
    <div class="search-audio 19"></div>
    <div class="search-audio 20"></div>
  </div>
</body>

</html>

0
投票

我认为你把它复杂化了一点，通过使用

:nth-child
将
.search-audio
的样式应用于类
.slide
的每个第三个div，可以只使用CSS。

这段代码可能是错误的，但类似于：

.slide:nth-child(3n) {
  /* move styles here from .search-audo */
}

这里有一些链接可能对学习如何使用它们有用：

0
投票

首先注意：类名不能是数字（

class="search-audio 1
）。

这里是一个片段，它使用 reducer 将元素分组为 3 个一组，然后将这些组包装在一个分组元素中。

// create groups of 3
const sliderGroups = [...document.querySelectorAll(`.search-audio`)]
  .reduce((acc, el, i) => {
    if (i && i%3 == 0) {
      acc = [...acc, []];
    }
    acc[acc.length - 1] = acc[acc.length - 1].concat(el);
    return acc;
  }, [[]]);
// now you have an array of arrays 
// with each 3 elements. Let's wrap
// those
wrap(sliderGroups);

function wrap (array) {
  // a wrapper base Node
  const wrapperElem = Object.assign(
    document.createElement(`div`), {className: `slideGroup`});
  const sliderCollection = document.querySelector(`.slider`);
  array.forEach( elemGroup => {
    // create a new wrapper Node from the base
    const wrap = wrapperElem.cloneNode();
    // append it to div.slider
    sliderCollection.append(wrap);
    // append *moves* the (life) elements of
    // the current group to the wrap element
    wrap.append(...elemGroup);
  });
}
.search-audio:after {
  content: "search-audio elem";
  color: red;
  margin-left: 6px;
}

.slideGroup:before {
  content: "slide group";
  color: green;
}
<div class="slider">
    <div class="search-audio"></div>
    <div class="search-audio"></div>
    <div class="search-audio"></div>
    <div class="search-audio"></div>
    <div class="search-audio"></div>
    <div class="search-audio"></div>
    <div class="search-audio"></div>
    <div class="search-audio"></div>
    <div class="search-audio"></div>
    <div class="search-audio]"></div>
    <div class="search-audio]"></div>
    <div class="search-audio"></div>
    <div class="search-audio"></div>
    <div class="search-audio"></div>
    <div class="search-audio"></div>
    <div class="search-audio"></div>
    <div class="search-audio"></div>
    <div class="search-audio"></div>
    <div class="search-audio"></div>
    <div class="search-audio"></div>
</div>

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