vue3数字动态变化效果

组件：

<CountTo
 :start="0" // 从数字多少开始
 :end="endCount" // 到数字多少结束
 :autoPlay="true" // 自动播放
 :duration="3000" // 过渡时间
 prefix="￥"   // 前缀符号
 suffix="rmb" // 后缀符号
 />

index.js

const UILib = {
  install(Vue) {
    Vue.component('CountTo', CountTo)
  }
}

export default UILib

main.js

import CountTo from './components/count-to/index';
app.use(CountTo)

requestAnimationFrame.js思路

1.先判断是不是浏览器还是其他环境
2.如果是浏览器判断浏览器内核类型
3.如果浏览器不支持requestAnimationFrame，cancelAnimationFrame方法，改写setTimeout定时器
4.导出两个方法 requestAnimationFrame, cancelAnimationFrame

各个浏览器前缀：let prefixes =  'webkit moz ms o';
判断是不是浏览器：let isServe = typeof window == 'undefined';
增加各个浏览器前缀：  
let prefix;
let requestAnimationFrame;
let cancelAnimationFrame;
// 通过遍历各浏览器前缀，来得到requestAnimationFrame和cancelAnimationFrame在当前浏览器的实现形式
    for (let i = 0; i < prefixes.length; i++) {
        if (requestAnimationFrame && cancelAnimationFrame) { break }
        prefix = prefixes[i]
        requestAnimationFrame = requestAnimationFrame || window[prefix + 'RequestAnimationFrame']
        cancelAnimationFrame = cancelAnimationFrame || window[prefix + 'CancelAnimationFrame'] || window[prefix + 'CancelRequestAnimationFrame']
    }
    
  //不支持使用setTimeout方式替换：模拟60帧的效果
  // 如果当前浏览器不支持requestAnimationFrame和cancelAnimationFrame，则会退到setTimeout
    if (!requestAnimationFrame || !cancelAnimationFrame) {
        requestAnimationFrame = function (callback) {
            const currTime = new Date().getTime()
            // 为了使setTimteout的尽可能的接近每秒60帧的效果
            const timeToCall = Math.max(0, 16 - (currTime - lastTime))
            const id = window.setTimeout(() => {
                callback(currTime + timeToCall)
            }, timeToCall)
            lastTime = currTime + timeToCall
            return id
        }

        cancelAnimationFrame = function (id) {
            window.clearTimeout(id)
        }
    }

完整代码

requestAnimationFrame.js

let lastTime = 0
const prefixes = 'webkit moz ms o'.split(' ') // 各浏览器前缀

let requestAnimationFrame
let cancelAnimationFrame

// 判断是否是服务器环境
const isServer = typeof window === 'undefined'
if (isServer) {
    requestAnimationFrame = function () {
        return
    }
    cancelAnimationFrame = function () {
        return
    }
} else {
    requestAnimationFrame = window.requestAnimationFrame
    cancelAnimationFrame = window.cancelAnimationFrame
    let prefix
    // 通过遍历各浏览器前缀，来得到requestAnimationFrame和cancelAnimationFrame在当前浏览器的实现形式
    for (let i = 0; i < prefixes.length; i++) {
        if (requestAnimationFrame && cancelAnimationFrame) { break }
        prefix = prefixes[i]
        requestAnimationFrame = requestAnimationFrame || window[prefix + 'RequestAnimationFrame']
        cancelAnimationFrame = cancelAnimationFrame || window[prefix + 'CancelAnimationFrame'] || window[prefix + 'CancelRequestAnimationFrame']
    }

    // 如果当前浏览器不支持requestAnimationFrame和cancelAnimationFrame，则会退到setTimeout
    if (!requestAnimationFrame || !cancelAnimationFrame) {
        requestAnimationFrame = function (callback) {
            const currTime = new Date().getTime()
            // 为了使setTimteout的尽可能的接近每秒60帧的效果
            const timeToCall = Math.max(0, 16 - (currTime - lastTime))
            const id = window.setTimeout(() => {
                callback(currTime + timeToCall)
            }, timeToCall)
            lastTime = currTime + timeToCall
            return id
        }

        cancelAnimationFrame = function (id) {
            window.clearTimeout(id)
        }
    }
}

export { requestAnimationFrame, cancelAnimationFrame }

首先引入requestAnimationFrame.js,使用requestAnimationFrame方法接受count函数，还需要格式化数字，进行正则表达式转换，返回我们想要的数据格式。

需要接受的参数：

const props = defineProps({
  start: {
    type: Number,
    required: false,
    default: 0
  },
  end: {
    type: Number,
    required: false,
    default: 0
  },
  duration: {
    type: Number,
    required: false,
    default: 5000
  },
  autoPlay: {
    type: Boolean,
    required: false,
    default: true
  },
  decimals: {
    type: Number,
    required: false,
    default: 0,
    validator (value) {
      return value >= 0
    }
  },
  decimal: {
    type: String,
    required: false,
    default: '.'
  },
  separator: {
    type: String,
    required: false,
    default: ','
  },
  prefix: {
    type: String,
    required: false,
    default: ''
  },
  suffix: {
    type: String,
    required: false,
    default: ''
  },
  useEasing: {
    type: Boolean,
    required: false,
    default: true
  },
  easingFn: {
    type: Function,
    default(t, b, c, d) {
      return c * (-Math.pow(2, -10 * t / d) + 1) * 1024 / 1023 + b;
    }
  }
})

const startCount = () => {
  state.localStart = props.start
  state.startTime = null
  state.localDuration = props.duration
  state.paused = false
  state.rAF = requestAnimationFrame(count)
}

  if (!state.startTime) state.startTime = timestamp
  state.timestamp = timestamp
  const progress = timestamp - state.startTime
  state.remaining = state.localDuration - progress
  // 是否使用速度变化曲线
  if (props.useEasing) {
    if (stopCount.value) {
      state.printVal = state.localStart - props.easingFn(progress, 0, state.localStart - props.end, state.localDuration)
    } else {
      state.printVal = props.easingFn(progress, state.localStart, props.end - state.localStart, state.localDuration)
    }
  } else {
    if (stopCount.value) {
      state.printVal = state.localStart - ((state.localStart - props.end) * (progress / state.localDuration))
    } else {
      state.printVal = state.localStart + (props.end - state.localStart) * (progress / state.localDuration)
    }
  }
  if (stopCount.value) {
    state.printVal = state.printVal < props.end ? props.end : state.printVal
  } else {
    state.printVal = state.printVal > props.end ? props.end : state.printVal
  }

  state.displayValue = formatNumber(state.printVal)
  if (progress < state.localDuration) {
    state.rAF = requestAnimationFrame(count)
  } else {
    emits('callback')
  }
}


// 格式化数据，返回想要展示的数据格式
const formatNumber = (val) => {
  val = val.toFixed(props.default)
  val += ''
  const x = val.split('.')
  let x1 = x[0]
  const x2 = x.length > 1 ? props.decimal + x[1] : ''
  const rgx = /(\d+)(\d{3})/
  if (props.separator && !isNumber(props.separator)) {
    while (rgx.test(x1)) {
      x1 = x1.replace(rgx, '$1' + props.separator + '$2')
    }
  }
  return props.prefix + x1 + x2 + props.suffix
}