shop-applet/uni_modules/uview-ui/components/u-count-down/u-count-down.vue

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<template>
<view class="u-count-down">
<slot>
<text class="u-count-down__text">{{ formattedTime }}</text>
</slot>
</view>
</template>
<script>
import props from './props.js';
import {
isSameSecond,
parseFormat,
parseTimeData
} from './utils';
/**
* u-count-down 倒计时
* @description 该组件一般使用于某个活动的截止时间上,通过数字的变化,给用户明确的时间感受,提示用户进行某一个行为操作。
* @tutorial https://uviewui.com/components/countDown.html
* @property {String | Number} time 倒计时时长单位ms (默认 0
* @property {String} format 时间格式DD-日HH-时mm-分ss-秒SSS-毫秒 (默认 'HH:mm:ss'
* @property {Boolean} autoStart 是否自动开始倒计时 (默认 true
* @property {Boolean} millisecond 是否展示毫秒倒计时 (默认 false
* @event {Function} finish 倒计时结束时触发
* @event {Function} change 倒计时变化时触发
* @event {Function} start 开始倒计时
* @event {Function} pause 暂停倒计时
* @event {Function} reset 重设倒计时,若 auto-start 为 true重设后会自动开始倒计时
* @example <u-count-down :time="time"></u-count-down>
*/
export default {
name: 'u-count-down',
mixins: [uni.$u.mpMixin, uni.$u.mixin, props],
data() {
return {
timer: null,
// 各单位(天,时,分等)剩余时间
timeData: parseTimeData(0),
// 格式化后的时间,如"03:23:21"
formattedTime: '0',
// 倒计时是否正在进行中
runing: false,
endTime: 0, // 结束的毫秒时间戳
remainTime: 0, // 剩余的毫秒时间
}
},
watch: {
time(n) {
this.reset()
}
},
mounted() {
this.init()
},
methods: {
init() {
this.reset()
},
// 开始倒计时
start() {
if (this.runing) return
// 标识为进行中
this.runing = true
// 结束时间戳 = 此刻时间戳 + 剩余的时间
this.endTime = Date.now() + this.remainTime
this.toTick()
},
// 根据是否展示毫秒,执行不同操作函数
toTick() {
if (this.millisecond) {
this.microTick()
} else {
this.macroTick()
}
},
macroTick() {
this.clearTimeout()
// 每隔一定时间,更新一遍定时器的值
// 同时此定时器的作用也能带来毫秒级的更新
this.timer = setTimeout(() => {
// 获取剩余时间
const remain = this.getRemainTime()
// 重设剩余时间
if (!isSameSecond(remain, this.remainTime) || remain === 0) {
this.setRemainTime(remain)
}
// 如果剩余时间不为0则继续检查更新倒计时
if (this.remainTime !== 0) {
this.macroTick()
}
}, 30)
},
microTick() {
this.clearTimeout()
this.timer = setTimeout(() => {
this.setRemainTime(this.getRemainTime())
if (this.remainTime !== 0) {
this.microTick()
}
}, 50)
},
// 获取剩余的时间
getRemainTime() {
// 取最大值防止出现小于0的剩余时间值
return Math.max(this.endTime - Date.now(), 0)
},
// 设置剩余的时间
setRemainTime(remain) {
this.remainTime = remain
// 根据剩余的毫秒时间,得出该有天,小时,分钟等的值,返回一个对象
const timeData = parseTimeData(remain)
this.$emit('change', timeData)
// 得出格式化后的时间
this.formattedTime = parseFormat(this.format, timeData)
// 如果时间已到,停止倒计时
if (remain <= 0) {
this.pause()
this.$emit('finish')
}
},
// 重置倒计时
reset() {
this.pause()
this.remainTime = this.time
this.setRemainTime(this.remainTime)
if (this.autoStart) {
this.start()
}
},
// 暂停倒计时
pause() {
this.runing = false;
this.clearTimeout()
},
// 清空定时器
clearTimeout() {
clearTimeout(this.timer)
this.timer = null
}
},
beforeDestroy() {
this.clearTimeout()
}
}
</script>
<style
lang="scss"
scoped
>
@import "../../libs/css/components.scss";
$u-count-down-text-color:$u-content-color !default;
$u-count-down-text-font-size:15px !default;
$u-count-down-text-line-height:22px !default;
.u-count-down {
&__text {
color: $u-count-down-text-color;
font-size: $u-count-down-text-font-size;
line-height: $u-count-down-text-line-height;
}
}
</style>