小程序-手机验证码倒计时

用的有赞组件

<van-cell-group> 
  <van-field
    value="{{ phone }}"
    label="手机号"
    placeholder="请输入手机号" 
    border="{{ false }}"
    bind:change="change"
  />
   <van-field
    value="{{ sms }}"
    center
    clearable
    label="短信验证码"
    placeholder="请输入短信验证码"
    border="{{ false }}"
    use-button-slot
    bind:change="change_code"
  >
    <van-button slot="button" wx:if="{{send_state}}" size="small" type="primary" bindtap='send'>发送验证码</van-button>
    <van-button slot="button" wx:else disabled size="small" type="default">{{miao}}秒</van-button>
    
  </van-field>
</van-cell-group>
<view class="c_t">
<van-button slot="button" size="small" type="danger" bindtap='sub'>绑定</van-button>
</view>

//我这里是封装的http，可直接用wx.request代替
import { HTTP } from '../../util/http.js';
const http = new HTTP

Page({

  data: {
    phone: "",
    code: "",
    send_state: true,
    smiao: 10
  },
  change(event) {
    const phone = event.detail;
    this.setData({
      phone
    })
  },
  change_code(event) {
    const code = event.detail;
    this.setData({
      code
    })
  },
  sub() {
    const phone = this.data.phone
    const code = this.data.code
    if(this.checkPhone(phone)<1){
      return;
    }
    if (code.length<4){
      wx.showToast({
        title: '验证码有误',
        icon: 'none',
        duration: 2000
      })
      return;
    }
    http.request({
      url:'',
      method:'post',
      data:{
        phone,
        code
      }
    })
  },
  send() {
    const that = this
    const phone = this.data.phone
    const check = this.checkPhone(phone)
    const smiao = that.data.smiao
    if (check == 1) {
      this.setData({
        send_state: false,
        miao: smiao
      })
      this.settime(smiao)
    }
  },
  checkPhone(phone) {
    if (!(/^1[34578]\d{9}$/.test(phone))) {
      wx.showToast({
        title: '手机号有误',
        icon: 'none',
        duration: 2000
      })
      return 0;
    } else {
      return 1;
    }
  },
  settime(miao) {
    const that = this
    const smiao = that.data.smiao
    if (miao == 0) {
      console.log('stop')
      that.setData({
        miao: smiao,
        send_state: true
      })
    } else {
      setTimeout(() => {
        miao--
        that.setData({
          miao
        })
        that.settime(miao)
      }, 1000)
    }

  }
})