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| <template>
| <transition :name="transitionName">
| <div v-show="visible" 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: '20px',
| bottom: '20px',
| width: '30px',
| height: '30px',
| 'border-radius': '4px',
| 'line-height': '35px',
| 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++
| }, 5)
| },
| 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;*/
| right: 20px;
| bottom: 20px;
| line-height: 35px;
| background: #fff;
| position: fixed;
| width: 40px;
| height: 40px;
| border-radius: 50%;
| color: #409eff;
| display: flex;
| align-items: center;
| justify-content: center;
| font-size: 20px;
| box-shadow: 0 0 6px rgba(0,0,0,.12);
| cursor: pointer;
| z-index: 5;
| }
|
| .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: #409eff;
| background: none;
| }
| </style>
|
|
