<!--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;