<!--pages/main/index.wxml--><view class="animate-number">
  <view class="num num1">{{num1}}{{num1Complete}}</view>
  <view class="num num2">{{num2}}{{num2Complete}}</view>
  <view class="num num3">{{num3}}{{num3Complete}}</view>
  <view class="btn-box">
  <button bindtap="animate" type="primary" class="button">click me</button>
  </view></view>

// pages/main/index.jsimport NumberAnimate from "../../utils/NumberAnimate";Page({
 data:{ 
 },
 onLoad:function(options){
  // 页面初始化 options为页面跳转所带来的参数 
 },
 onReady:function(){ 
 },
 onShow:function(){
 
  // 页面显示
 },
 onHide:function(){
  // 页面隐藏
 }, 
 onUnload:function(){
  // 页面关闭 
 },
 //调用NumberAnimate.js中NumberAnimate实例化对象，测试3种效果
 animate:function(){
 
  this.setData({
   num1:'',
   num2:'',
   num3:'',
   num1Complete:'',
   num2Complete:'',
   num3Complete:''
  });
 
  let num1 = 18362.856;
  let n1 = new NumberAnimate({
    from:num1,//开始时的数字
    speed:2000,// 总时间
    refreshTime:100,// 刷新一次的时间
    decimals:3,//小数点后的位数
    onUpdate:()=>{//更新回调函数
     this.setData({
      num1:n1.tempValue     });
    },
    onComplete:()=>{//完成回调函数
      this.setData({
       num1Complete:" 完成了"
      });
    }
  });
 
  let num2 = 13388;
  let n2 = new NumberAnimate({
    from:num2,
    speed:1500,
    decimals:0,
    refreshTime:100,
    onUpdate:()=>{
     this.setData({
      num2:n2.tempValue     });
    },
    onComplete:()=>{
      this.setData({
       num2Complete:" 完成了"
      });
    }
  });
 
  let num3 = 2123655255888.86;
  let n3 = new NumberAnimate({
    from:num3,
    speed:2000,
    refreshTime:100,
    decimals:2,
    onUpdate:()=>{
     this.setData({
      num3:n3.tempValue     });
    },
    onComplete:()=>{
      this.setData({
       num3Complete:" 完成了"
      });
    }
  });
 }})

/**
 * Created by wangyy on 2016/12/26.
 */'use strict';class NumberAnimate {
 
  constructor(opt) {
    let def = {
      from:50,//开始时的数字
      speed:2000,// 总时间
      refreshTime:100,// 刷新一次的时间
      decimals:2,// 小数点后的位数
      onUpdate:function(){}, // 更新时回调函数
      onComplete:function(){} // 完成时回调函数
    }
    this.tempValue = 0;//累加变量值
    this.opt = Object.assign(def,opt);//assign传入配置参数
    this.loopCount = 0;//循环次数计数
    this.loops = Math.ceil(this.opt.speed/this.opt.refreshTime);//数字累加次数
    this.increment = (this.opt.from/this.loops);//每次累加的值
    this.interval = null;//计时器对象
    this.init();
  }
  init(){
    this.interval = setInterval(()=>{this.updateTimer()},this.opt.refreshTime);
  }
 
  updateTimer(){
 
    this.loopCount++;
    this.tempValue = this.formatFloat(this.tempValue,this.increment).toFixed(this.opt.decimals);
    if(this.loopCount >= this.loops){
      clearInterval(this.interval);
      this.tempValue = this.opt.from;
      this.opt.onComplete();
    }
    this.opt.onUpdate();
  }
  //解决0.1+0.2不等于0.3的小数累加精度问题
  formatFloat(num1, num2) {
    let baseNum, baseNum1, baseNum2;
    try {
      baseNum1 = num1.toString().split(".")[1].length;
    } catch (e) {
      baseNum1 = 0;
    }
    try {
      baseNum2 = num2.toString().split(".")[1].length;
    } catch (e) {
      baseNum2 = 0;
    }
    baseNum = Math.pow(10, Math.max(baseNum1, baseNum2));
    return (num1 * baseNum + num2 * baseNum) / baseNum;
  };}export default NumberAnimate;