Vue3加载条（LoadingBar）

效果如下图：在线预览

APIs

LoadingBar

Methods

创建加载条组件LoadingBar.vue

<script setup lang="ts">
import { ref, nextTick } from 'vue'
import type { CSSProperties } from 'vue'
interface Props {
  containerClass?: string // 加载条容器的类名
  containerStyle?: CSSProperties // 加载条容器的样式
  loadingBarSize?: number // 加载条大小，单位 px
  colorLoading?: string // 加载中颜色
  colorFinish?: string // 加载完成颜色
  colorError?: string // 加载错误颜色
  to?: string | HTMLElement // 加载条的挂载位置，可选：元素标签名（例如 body）或者元素本身
}
withDefaults(defineProps<Props>(), {
  containerClass: undefined,
  containerStyle: () => ({}),
  loadingBarSize: 2,
  colorLoading: '#1677ff',
  colorFinish: '#1677ff',
  colorError: '#ff4d4f',
  to: 'body'
})
const showLoadingBar = ref(false)
const loadingBarRef = ref() // 加载条 DOM 引用
const loadingStarted = ref(false) // 加载条是否开始
const loadingFinishing = ref(false) // 加载条是否完成
const loadingErroring = ref(false) // 加载条是否报错
async function init() {
  showLoadingBar.value = false
  loadingFinishing.value = false
  loadingErroring.value = false
}
async function start(from = 0, to = 80, status: 'starting' | 'error' = 'starting') {
  // 加载条开始加载的回调函数
  loadingStarted.value = true
  await init()
  if (loadingFinishing.value) {
    return
  }
  showLoadingBar.value = true
  await nextTick()
  if (!loadingBarRef.value) {
    return
  }
  loadingBarRef.value.style.transition = 'none' // 禁用过渡
  loadingBarRef.value.style.maxWidth = `${from}%`
  void loadingBarRef.value.offsetWidth // 触发浏览器回流(重排)
  loadingBarRef.value.className = `loading-bar loading-bar-${status}`
  loadingBarRef.value.style.transition = ''
  loadingBarRef.value.style.maxWidth = `${to}%`
}
async function finish() {
  // 加载条结束加载的回调函数
  if (loadingFinishing.value || loadingErroring.value) {
    return
  }
  if (loadingStarted.value) {
    await nextTick()
  }
  loadingFinishing.value = true
  if (!loadingBarRef.value) {
    return
  }
  loadingBarRef.value.className = 'loading-bar loading-bar-finishing'
  loadingBarRef.value.style.maxWidth = '100%'
  void loadingBarRef.value.offsetWidth // 触发浏览器回流(重排)
  showLoadingBar.value = false
}
function error() {
  // 加载条出现错误的回调函数
  if (loadingFinishing.value || loadingErroring.value) {
    return
  }
  if (!showLoadingBar.value) {
    void start(100, 100, 'error').then(() => {
      loadingErroring.value = true
    })
  } else {
    loadingErroring.value = true
    if (!loadingBarRef.value) {
      return
    }
    loadingBarRef.value.className = 'loading-bar loading-bar-error'
    loadingBarRef.value.style.maxWidth = '100%'
    void loadingBarRef.value.offsetWidth
    showLoadingBar.value = false
  }
}
function onAfterEnter() {
  if (loadingErroring.value) {
    showLoadingBar.value = false
  }
}
async function onAfterLeave() {
  await init()
}
defineExpose({
  start,
  finish,
  error
})
</script>
<template>
  <Teleport :disabled="!to" :to="to">
    <Transition name="fade-in" @after-enter="onAfterEnter" @after-leave="onAfterLeave">
      <div v-show="showLoadingBar" class="m-loading-bar-container" :class="containerClass" :style="containerStyle">
        <div
          ref="loadingBarRef"
          class="loading-bar"
          :style="`--loading-bar-size: ${loadingBarSize}px; --color-loading: ${colorLoading}; --color-finish: ${colorFinish}; --color-error: ${colorError}; max-width: 100%;`"
        ></div>
      </div>
    </Transition>
  </Teleport>
</template>
<style lang="less" scoped>
.fade-in-enter-active {
  transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}
.fade-in-leave-active {
  transition: all 0.8s cubic-bezier(0.4, 0, 0.2, 1);
}
.fade-in-enter-from,
.fade-in-leave-to {
  opacity: 0;
}
.m-loading-bar-container {
  z-index: 9999;
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  height: var(--loading-bar-size);
  .loading-bar {
    width: 100%;
    transition:
      max-width 4s linear,
      background 0.2s linear;
    height: var(--loading-bar-size);
    border-radius: var(--loading-bar-size);
  }
  .loading-bar-starting {
    background: var(--color-loading);
  }
  .loading-bar-finishing {
    background: var(--color-finish);
    transition:
      max-width 0.2s linear,
      background 0.2s linear;
  }
  .loading-bar-error {
    background: var(--color-error);
    transition:
      max-width 0.2s linear,
      background 0.2s linear;
  }
}
</style>

在要使用的页面引入

其中引入使用了以下组件：

• Vue3间距（Space）
• Vue3按钮（Button）

<script setup lang="ts">
import LoadingBar from './LoadingBar.vue'
import { ref } from 'vue'
const loadingBar = ref()
const disabled = ref(true)
const localCardRef = ref()
const localLoadingBar = ref()
const customLoadingBar = ref()
function handleStart() {
  loadingBar.value.start()
  disabled.value = false
}
function handleFinish() {
  loadingBar.value.finish()
  disabled.value = true
}
function handleError() {
  disabled.value = true
  loadingBar.value.error()
}
</script>
<template>
  <div>
    <h1>{
  { $route.name }} {
  { $route.meta.title }}</h1>
    <h2 class="mt30 mb10">基本使用</h2>
    <Space>
      <Button type="primary" @click="handleStart">开始</Button>
      <Button :disabled="disabled" @click="handleFinish">结束</Button>
      <Button type="danger" @click="handleError">报个错</Button>
    </Space>
    <LoadingBar ref="loadingBar" />
    <h2 class="mt30 mb10">局部加载条</h2>
    <div class="m-container" ref="localCardRef">
      <Space>
        <Button type="primary" @click="localLoadingBar.start()">Start</Button>
        <Button @click="localLoadingBar.finish()">Finish</Button>
        <Button type="danger" @click="localLoadingBar.error()">Error</Button>
      </Space>
    </div>
    <LoadingBar ref="localLoadingBar" :container-style="{ position: 'absolute' }" :to="localCardRef" />
    <h2 class="mt30 mb10">自定义加载条样式</h2>
    <Space>
      <Button type="primary" @click="customLoadingBar.start()">Start</Button>
      <Button @click="customLoadingBar.finish()">Finish</Button>
      <Button type="danger" @click="customLoadingBar.error()">Error</Button>
    </Space>
    <LoadingBar
      ref="customLoadingBar"
      :loading-bar-size="5"
      color-loading="#2db7f5"
      color-finish="#52c41a"
      color-error="magenta"
    />
  </div>
</template>
<style lang="less" scoped>
.m-container {
  position: relative;
  display: flex;
  align-items: center;
  height: 200px;
  padding: 16px 24px;
  border: 1px solid #d9d9d9;
}
</style>