react.js每第n个项目添加开始标记或结束标记

问题描述

由于react / jsx不允许将非结束标记添加到数组/子组件，因此我在此逻辑中遇到了问题。例如，用bootstrap css，我想为每列添加一行 4列。

所以逻辑如下：

I'm having trouble with this logic since react/jsx does not allow for non closing tags to be added to an array/child component. For example with bootstrap css I want to add a row for every 4 columns.

添加一个开始行例如：< div className =row> ，然后在此行内循环，每个循环附加一个当循环达到4时检查< div className =列> {this.data}< / div> if（i ％4 == 0）并添加结束< / div> 标记，同时添加新的行标记< div className =row> ;

So the logic is as follows:

另一种语言，但在作出反应这是不可行的，因为我们推一个结束标签和一个开始标签（这是无效的jsx）：

Add a opening row ex: <div className="row">, then loop inside this row and every loop append a column ex: <div className="column>{this.data}</div> when the loop reaches 4 check with if(i % 4 == 0) and add a closing </div> tag while adding new row tag <div className="row">;

The code below would work in another language but in react this is not doable since we push a closing tag and a opening tag (which is invalid jsx):

）
}

预期输出为：

The expected output would be:

<div class="row">
  <div class="column">
   Some data
  </div>
  <div class="column">
   Some more data
  </div>
  <div class="column">
   Other data
  </div>
  <div class="column">
   Something else
  </div>
</div>
<div class="row">
  <div class="column">
   Some data
  </div>
  <div class="column">
   Some more data
  </div>
  <div class="column">
   Other data
  </div>
  <div class="column">
   Something else
  </div>
</div>

//上面的内容会重复出现，并且每隔4列。

推荐答案

render() {
   const rows = array_chunk(this.props.columns, 4)
   return (
     {
       rows.map((row) => (
         <div className="row">
         {
           row.map((col) => (
             <div className="col">{ col }</div>
           ))
         }
         </div>
       ))
     }
   )
}

一个array_chunk示例（我建议您使用lodash）

An example array_chunk (I recommend that you use lodash)

module.exports = function chunks(arr, size) {
  if (!Array.isArray(arr)) {
    throw new TypeError('Input should be Array');
  }

  if (typeof size !== 'number') {
    throw new TypeError('Size should be a Number');
  }

  var result = [];
  for (var i = 0; i < arr.length; i += size) {
    result.push(arr.slice(i, size + i));
  }

  return result;
};

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