<template>
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<text
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class="u-count-num"
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:style="{
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fontSize: $u.addUnit(fontSize),
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fontWeight: bold ? 'bold' : 'normal',
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color: color
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}"
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>{{ displayValue }}</text>
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</template>
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<script>
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import props from './props.js';
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/**
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* countTo 数字滚动
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* @description 该组件一般用于需要滚动数字到某一个值的场景，目标要求是一个递增的值。
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* @tutorial https://www.uviewui.com/components/countTo.html
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* @property {String | Number} startVal 开始的数值，默认从0增长到某一个数（默认 0 ）
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* @property {String | Number} endVal 要滚动的目标数值，必须 （默认 0 ）
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* @property {String | Number} duration 滚动到目标数值的动画持续时间，单位为毫秒（ms） （默认 2000 ）
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* @property {Boolean} autoplay 设置数值后是否自动开始滚动 （默认 true ）
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* @property {String | Number} decimals 要显示的小数位数，见官网说明（默认 0 ）
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* @property {Boolean} useEasing 滚动结束时，是否缓动结尾，见官网说明（默认 true ）
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* @property {String} decimal 十进制分割 （ 默认 "." ）
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* @property {String} color 字体颜色（ 默认 '#606266' )
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* @property {String | Number} fontSize 字体大小，单位px（ 默认 22 ）
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* @property {Boolean} bold 字体是否加粗（默认 false ）
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* @property {String} separator 千位分隔符，见官网说明
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* @event {Function} end 数值滚动到目标值时触发
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* @example <u-count-to ref="uCountTo" :end-val="endVal" :autoplay="autoplay"></u-count-to>
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*/
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export default {
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name: 'u-count-to',
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data() {
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return {
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localStartVal: this.startVal,
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displayValue: this.formatNumber(this.startVal),
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printVal: null,
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paused: false, // 是否暂停
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localDuration: Number(this.duration),
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startTime: null, // 开始的时间
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timestamp: null, // 时间戳
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remaining: null, // 停留的时间
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rAF: null,
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lastTime: 0 // 上一次的时间
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};
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},
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mixins: [uni.$u.mpMixin, uni.$u.mixin,props],
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computed: {
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countDown() {
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return this.startVal > this.endVal;
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}
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},
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watch: {
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startVal() {
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this.autoplay && this.start();
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},
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endVal() {
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this.autoplay && this.start();
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}
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},
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mounted() {
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this.autoplay && this.start();
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},
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methods: {
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easingFn(t, b, c, d) {
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return (c * (-Math.pow(2, (-10 * t) / d) + 1) * 1024) / 1023 + b;
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},
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requestAnimationFrame(callback) {
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const currTime = new Date().getTime();
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// 为了使setTimteout的尽可能的接近每秒60帧的效果
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const timeToCall = Math.max(0, 16 - (currTime - this.lastTime));
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const id = setTimeout(() => {
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callback(currTime + timeToCall);
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}, timeToCall);
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this.lastTime = currTime + timeToCall;
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return id;
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},
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cancelAnimationFrame(id) {
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clearTimeout(id);
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},
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// 开始滚动数字
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start() {
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this.localStartVal = this.startVal;
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this.startTime = null;
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this.localDuration = this.duration;
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this.paused = false;
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this.rAF = this.requestAnimationFrame(this.count);
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},
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// 暂定状态，重新再开始滚动；或者滚动状态下，暂停
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reStart() {
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if (this.paused) {
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this.resume();
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this.paused = false;
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} else {
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this.stop();
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this.paused = true;
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}
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},
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// 暂停
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stop() {
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this.cancelAnimationFrame(this.rAF);
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},
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// 重新开始(暂停的情况下)
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resume() {
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if (!this.remaining) return
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this.startTime = 0;
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this.localDuration = this.remaining;
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this.localStartVal = this.printVal;
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this.requestAnimationFrame(this.count);
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},
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// 重置
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reset() {
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this.startTime = null;
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this.cancelAnimationFrame(this.rAF);
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this.displayValue = this.formatNumber(this.startVal);
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},
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count(timestamp) {
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if (!this.startTime) this.startTime = timestamp;
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this.timestamp = timestamp;
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const progress = timestamp - this.startTime;
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this.remaining = this.localDuration - progress;
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if (this.useEasing) {
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if (this.countDown) {
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this.printVal = this.localStartVal - this.easingFn(progress, 0, this.localStartVal - this.endVal, this.localDuration);
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} else {
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this.printVal = this.easingFn(progress, this.localStartVal, this.endVal - this.localStartVal, this.localDuration);
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}
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} else {
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if (this.countDown) {
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this.printVal = this.localStartVal - (this.localStartVal - this.endVal) * (progress / this.localDuration);
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} else {
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this.printVal = this.localStartVal + (this.endVal - this.localStartVal) * (progress / this.localDuration);
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}
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}
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if (this.countDown) {
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this.printVal = this.printVal < this.endVal ? this.endVal : this.printVal;
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} else {
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this.printVal = this.printVal > this.endVal ? this.endVal : this.printVal;
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}
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this.displayValue = this.formatNumber(this.printVal) || 0;
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if (progress < this.localDuration) {
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this.rAF = this.requestAnimationFrame(this.count);
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} else {
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this.$emit('end');
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}
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},
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// 判断是否数字
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isNumber(val) {
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return !isNaN(parseFloat(val));
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},
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formatNumber(num) {
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// 将num转为Number类型，因为其值可能为字符串数值，调用toFixed会报错
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num = Number(num);
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num = num.toFixed(Number(this.decimals));
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num += '';
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const x = num.split('.');
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let x1 = x[0];
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const x2 = x.length > 1 ? this.decimal + x[1] : '';
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const rgx = /(\d+)(\d{3})/;
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if (this.separator && !this.isNumber(this.separator)) {
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while (rgx.test(x1)) {
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x1 = x1.replace(rgx, '$1' + this.separator + '$2');
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}
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}
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return x1 + x2;
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},
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destroyed() {
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this.cancelAnimationFrame(this.rAF);
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}
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}
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};
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</script>
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<style lang="scss" scoped>
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@import "../../libs/css/components.scss";
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.u-count-num {
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/* #ifndef APP-NVUE */
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display: inline-flex;
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/* #endif */
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text-align: center;
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}
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</style>
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