前端

嵌套结构的处理与渲染

公司组件库项目，有个同事做菜单功能，处理迭代弄不好。我写了一个简单的 DEMO，同时放出来参考：

在这里查看效果 JSFiddle

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<!DOCTYPE html>
<html>
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>Test</title>
    <style>
        .lv1 {
            margin: 10px 10px;
            border: 1px solid #ccc;
        }

        .lv2 {
            margin: 10px 20px;
            border: 1px solid #ccc;
        }

        .lv3 {
            margin: 10px 30px;
            border: 1px solid #ccc;
        }
    </style>
</head>
<body>
<div id="nav">
    <div data-color="red">1</div>
    <div>
        <div data-color="blue">2 - 1</div>
        <div data-color="purple">2 - 2</div>
        <div data-color="black">2 - 3</div>
    </div>
    <div>
        <div data-color="magenta">3 - 1</div>
        <div>
            <div data-color="green">3 - 2 - 1</div>
            <div data-color="brown">3 - 2 - 2</div>
        </div>
    </div>
</div>

<script>
  const rootElement = el => {
    if (typeof el === 'string') {
      return document.querySelector(el)
    }
    return el
  }

  const AST = root => {
    const children = (el, lv = 0) => {
      let color = el.dataset.color || null
      let text = null
      let child = el.children
      if (child.length === 0) text = el.textContent
      return {
        color,
        text,
        lv: lv,
        children: Array.prototype.map.call(child, v => children(v, lv + 1))
      }
    }
    return children(root).children
  }

  const render = list => {
    const htmlArr = children => {
      return children.map(child => {
        let color = child.color
        let text = child.text
        let ch = child.children
        let lv = child.lv
        if (ch.length > 0) {
          return `<div class="lv${lv}">${htmlArr(ch)}</div>`
        } else {
          return `<div class="lv${lv}" style="color:${color}">${text}</div>`
        }
      }).join('')
    }
    return htmlArr(list)
  }

  class Test {
    constructor (el) {
      let $el = rootElement(el)
      let list = AST($el)
      console.log(list)
      let html = render(list)
      console.log(html)
      $el.innerHTML = html
    }
  }
</script>

<script>
  new Test('#nav')
</script>
</body>
</html>