计算Vue插槽的高度和宽度

Question

我遇到了计算插槽高度和宽度的问题。我尝试在我的Perimeter组件中渲染图像，这些图像的大小为105x160。但是当我使用console.log记录clientWidth和clientHeight时，得到的结果是0x24。

我认为我的问题与此有关：在vue.js 2中，测量一次插槽被渲染后组件的高度，但我仍然无法弄清楚。我已经尝试在Perimeter组件和单个插槽组件上使用$nextTick。

在我的Perimeter组件中，我有：

<template>
  <div class="d-flex">
    <slot></slot>
    <div class="align-self-center">
      <slot name="center-piece"></slot>
    </div>
  </div>
</template>

<script>
  export default {
    name: 'Perimeter',
    mounted() {
      this.distributeSlots();
    },
    updated() {
      this.distributeSlots();
    },
    computed: {
      centerRadius() {
        return this.$slots['center-piece'][0].elm.clientWidth / 2;
      },
    },
    methods: {
      distributeSlots() {
        let angle = 0;
        const {
          clientHeight: componentHeight,
          clientWidth: componentWidth,
          offsetTop: componentOffsetTop,
          offsetLeft: componentOffsetLeft,
        } = this.$el;
        const componentXCenter = componentWidth / 2;
        const componentYCenter = componentHeight / 2;

        const slots = this.$slots.default.filter(slot => slot.tag) || [];
        const step = (2 * Math.PI) / slots.length;

        slots.forEach((slot) => {
          slot.context.$nextTick(() => {
            const { height, width } = slot.elm.getBoundingClientRect();
            console.log(`height ${height}, width ${width}`);
            const distanceFromCenterX = (this.centerRadius + componentXCenter) * Math.cos(angle);
            const distanceFromCenterY = (this.centerRadius + componentYCenter) * Math.sin(angle);
            const x = Math.round((componentXCenter + distanceFromCenterX + componentOffsetLeft) - (width / 2));
            const y = Math.round((componentYCenter + distanceFromCenterY + componentOffsetTop) - (height / 2));

            slot.elm.style.left = `${x}px`;
            slot.elm.style.top = `${y}px`;

            angle += step;
          });
        });
      },
    },
  };
</script>

我也曾经编写过没有使用$nextTick的distributeSlots()方法：

distributeSlots() {
  let angle = 0;
  const {
    clientHeight: componentHeight,
    clientWidth: componentWidth,
    offsetTop: componentOffsetTop,
    offsetLeft: componentOffsetLeft,
  } = this.$el;
  const componentXCenter = componentWidth / 2;
  const componentYCenter = componentHeight / 2;

  const slots = this.$slots.default.filter(slot => slot.tag) || [];
  const step = (2 * Math.PI) / slots.length;

  slots.forEach((slot) => {
    const { height, width } = slot.elm.getBoundingClientRect();
    const distanceFromCenterX = (this.centerRadius + componentXCenter) * Math.cos(angle);
    const distanceFromCenterY = (this.centerRadius + componentYCenter) * Math.sin(angle);
    const x = Math.round((componentXCenter + distanceFromCenterX + componentOffsetLeft) - (width / 2));
    const y = Math.round((componentYCenter + distanceFromCenterY + componentOffsetTop) - (height / 2));

    slot.elm.style.left = `${x}px`;
    slot.elm.style.top = `${y}px`;

    angle += step;
  });
},

我将以下内容传递给 Perimeter 组件：

我将以下内容传递给 Perimeter 组件：

<template>
  <perimeter>
    <div v-for="(book, index) in books.slice(0, 6)" v-if="book.image" :key="book.asin" style="position: absolute">
      <router-link :to="{ name: 'books', params: { isbn: book.isbn }}">
        <img :src="book.image" />
      </router-link>
    </div>
  <perimeter>
</template>

更糟糕的是，当我在forEach函数中使用console.log(slot.elm)并在浏览器控制台中打开该数组时，我可以看到正确的clientHeight和clientWidth：

- AryanJ-NYC

Answer 1

通常这种情况不是框架的问题，而是逻辑错误。因此，我建议对代码进行简化，只保留最少量能够演示你的问题。

假设你在mounted()或之后获取clientWidth和clientHeight，如下面所示，它应该可以正常工作。

避免任何定时器 hack，它们是极难调试的 bug 的罪魁祸首。

<template>
  <div style="min-height: 100px; min-width: 100px;">
    <slot />
  </div>
</template>

<script>
export default {
  name: 'MyContainer',
  data (){
    return {
      width: 0,
      height: 0,
    }
  },
  mounted (){
    this.width = this.$slots["default"][0].elm.clientWidth
    this.height = this.$slots["default"][0].elm.clientHeight
    console.log(this.width, this.height)  // => 100 100 (or more)
  },

}
</script>

<style scoped lang="scss">
</style>

- Pithikos

Answer 2

你可以使用一个技巧，将代码放在 setTimeout 方法中，在另一个线程中以微小的延迟执行：

setTimeout(() => {
     // Put your code here
     ...
}, 80)

- Sasan Farrokh

---

这是一种不可靠的黑客方式，无法解决手头的问题。 - Pithikos

是的，但值得一提。 - Sasan Farrokh

如果DOM更新实际上需要超过80毫秒的时间怎么办？ - Pithikos