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| <template>
| <transition :name="transitionName">
| <div v-show="visible" :style="customStyle" class="back-to-ceiling" @click="backToTop">
| <svg width="16" height="16" viewBox="0 0 17 17" xmlns="http://www.w3.org/2000/svg" class="Icon Icon--backToTopArrow" aria-hidden="true" style="height:16px;width:16px"><path d="M12.036 15.59a1 1 0 0 1-.997.995H5.032a.996.996 0 0 1-.997-.996V8.584H1.03c-1.1 0-1.36-.633-.578-1.416L7.33.29a1.003 1.003 0 0 1 1.412 0l6.878 6.88c.782.78.523 1.415-.58 1.415h-3.004v7.004z" /></svg>
| </div>
| </transition>
| </template>
|
| <script>
| export default {
| name: 'BackToTop',
| props: {
| visibilityHeight: {
| type: Number,
| default: 400
| },
| backPosition: {
| type: Number,
| default: 0
| },
| customStyle: {
| type: Object,
| default: function() {
| return {
| right: '50px',
| bottom: '50px',
| width: '40px',
| height: '40px',
| 'border-radius': '4px',
| 'line-height': '45px',
| background: '#e7eaf1'
| }
| }
| },
| transitionName: {
| type: String,
| default: 'fade'
| }
| },
| data() {
| return {
| visible: false,
| interval: null,
| isMoving: false
| }
| },
| mounted() {
| window.addEventListener('scroll', this.handleScroll)
| },
| beforeDestroy() {
| window.removeEventListener('scroll', this.handleScroll)
| if (this.interval) {
| clearInterval(this.interval)
| }
| },
| methods: {
| handleScroll() {
| this.visible = window.pageYOffset > this.visibilityHeight
| },
| backToTop() {
| if (this.isMoving) return
| const start = window.pageYOffset
| let i = 0
| this.isMoving = true
| this.interval = setInterval(() => {
| const next = Math.floor(this.easeInOutQuad(10 * i, start, -start, 500))
| if (next <= this.backPosition) {
| window.scrollTo(0, this.backPosition)
| clearInterval(this.interval)
| this.isMoving = false
| } else {
| window.scrollTo(0, next)
| }
| i++
| }, 16.7)
| },
| easeInOutQuad(t, b, c, d) {
| if ((t /= d / 2) < 1) return c / 2 * t * t + b
| return -c / 2 * (--t * (t - 2) - 1) + b
| }
| }
| }
| </script>
|
| <style scoped>
| .back-to-ceiling {
| position: fixed;
| display: inline-block;
| text-align: center;
| cursor: pointer;
| }
|
| .back-to-ceiling:hover {
| background: #d5dbe7;
| }
|
| .fade-enter-active,
| .fade-leave-active {
| transition: opacity .5s;
| }
|
| .fade-enter,
| .fade-leave-to {
| opacity: 0
| }
|
| .back-to-ceiling .Icon {
| fill: #9aaabf;
| background: none;
| }
| </style>
|
|
