545 lines
22 KiB
Vue
545 lines
22 KiB
Vue
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<template>
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<div :ref="elementRef" :class="containerClass" :style="style" @scroll="onScroll">
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<div :ref="contentRef" class="p-virtualscroller-content">
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<template v-for="(item, index) of renderItems" :key="index">
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<slot name="item" :item="item" :options="getOptions(index)"></slot>
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</template>
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</div>
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<div :ref="spacerRef" class="p-virtualscroller-spacer"></div>
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<div :class="loaderClass" v-if="d_loading">
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<template v-for="(loadItem, index) of loaderArr" :key="index">
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<slot name="loader" :options="getLoaderOptions(index)">
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<i class="p-virtualscroller-loading-icon pi pi-spinner pi-spin"></i>
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</slot>
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</template>
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</div>
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</div>
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</template>
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<script>
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export default {
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name: 'VirtualScroller',
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emits: ['update:numToleratedItems', 'scroll-index-change', 'lazy-load'],
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props: {
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items: null,
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itemSize: {
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type: [Number,Array],
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default: null
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},
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scrollHeight: null,
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scrollWidth: null,
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orientation: {
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type: String,
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default: 'vertical'
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},
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numToleratedItems: {
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type: Number,
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default: null
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},
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delay: {
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type: Number,
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default: 0
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},
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lazy: {
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type: Boolean,
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default: false
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},
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showLoader: {
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type: Boolean,
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default: false
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},
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loading: {
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type: Boolean,
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default: false
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},
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style: null,
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class: null
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},
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data() {
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return {
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first: this.isBoth() ? { rows: 0, cols: 0 } : 0,
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last: this.isBoth() ? { rows: 0, cols: 0 } : 0,
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numItemsInViewport: this.isBoth() ? { rows: 0, cols: 0 } : 0,
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lastScrollPos: this.isBoth() ? { top: 0, left: 0 } : 0,
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d_numToleratedItems: this.numToleratedItems,
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d_loading: this.loading,
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loaderArr: null
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}
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},
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element: null,
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content: null,
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spacer: null,
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scrollTimeout: null,
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mounted() {
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this.$nextTick(function () {
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this.init();
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});
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},
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watch: {
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numToleratedItems(newValue) {
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this.d_numToleratedItems = newValue;
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},
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loading(newValue) {
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this.d_loading = newValue;
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}
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},
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methods: {
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init() {
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this.setSize();
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this.calculateOptions();
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this.setSpacerSize();
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},
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getLast(last, isCols) {
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return this.items ? Math.min((isCols ? this.items[0].length : this.items.length), last) : 0;
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},
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calculateOptions() {
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const isBoth = this.isBoth();
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const isHorizontal = this.isHorizontal();
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const first = this.first;
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const itemSize = this.itemSize;
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const contentPadding = this.getContentPadding();
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const contentWidth = this.element ? this.element.offsetWidth - contentPadding.left : 0;
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const contentHeight = this.element ? this.element.offsetHeight - contentPadding.top : 0;
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const calculateNumItemsInViewport = (_contentSize, _itemSize) => Math.ceil(_contentSize / (_itemSize || _contentSize));
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const numItemsInViewport = isBoth ?
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{ rows: calculateNumItemsInViewport(contentHeight, itemSize[0]), cols: calculateNumItemsInViewport(contentWidth, itemSize[1]) } :
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calculateNumItemsInViewport((isHorizontal ? contentWidth : contentHeight), itemSize);
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let numToleratedItems = this.d_numToleratedItems || Math.ceil((isBoth ? numItemsInViewport.rows : numItemsInViewport) / 2);
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const calculateLast = (_first, _num, _isCols) => this.getLast(_first + _num + ((_first < numToleratedItems ? 2 : 3) * numToleratedItems), _isCols);
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const last = isBoth ?
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{ rows: calculateLast(first.rows, numItemsInViewport.rows), cols: calculateLast(first.cols, numItemsInViewport.cols, true) } :
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calculateLast(first, numItemsInViewport);
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this.d_numToleratedItems = numToleratedItems;
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this.$emit('update:numToleratedItems', this.d_numToleratedItems);
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this.last = last;
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this.numItemsInViewport = numItemsInViewport;
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if (this.showLoader) {
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if (this.$slots && this.$slots.loader) {
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this.loaderArr = Array.from({ length: (isBoth ? numItemsInViewport.rows : numItemsInViewport) });
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}
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else {
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this.loaderArr = Array.from({ length: 1});
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}
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}
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if (this.lazy) {
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this.$emit('lazy-load', { first, last });
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}
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},
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getContentPadding() {
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if (this.content) {
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const style = getComputedStyle(this.content);
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const left = parseInt(parseFloat(style.paddingLeft.slice(0, -2)), 10);
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const right = parseInt(parseFloat(style.paddingRight.slice(0, -2)), 10);
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const top = parseInt(parseFloat(style.paddingTop.slice(0, -2)), 10);
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const bottom = parseInt(parseFloat(style.paddingBottom.slice(0, -2)), 10);
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return { left, right, top, bottom, x: left + right, y: top + bottom };
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}
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return { left: 0, right: 0, top: 0, bottom: 0, x: 0, y: 0 };
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},
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setSize() {
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if (this.element) {
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const isBoth = this.isBoth();
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const isHorizontal = this.isHorizontal();
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const parentElement = this.element.parentElement;
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const width = this.scrollWidth || `${(this.element.offsetWidth || parentElement.offsetWidth)}px`;
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const height = this.scrollHeight || `${(this.element.offsetHeight || parentElement.offsetHeight)}px`;
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const setProp = (_name, _value) => this.element.style[_name] = _value;
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if (isBoth) {
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setProp('height', height);
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setProp('width', width);
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}
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else {
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isHorizontal ? setProp('width', width) : setProp('height', height);
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}
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}
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},
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setSpacerSize() {
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const items = this.items;
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if (this.spacer && items) {
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const isBoth = this.isBoth();
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const isHorizontal = this.isHorizontal();
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const itemSize = this.itemSize;
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const contentPadding = this.getContentPadding();
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const setProp = (_name, _value, _size, _padding = 0) => this.spacer.style[_name] = (((_value || []).length * _size) + _padding) + 'px';
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if (isBoth) {
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setProp('height', items[0], itemSize[0], contentPadding.y);
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setProp('width', items[1], itemSize[1], contentPadding.x);
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}
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else {
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isHorizontal ? setProp('width', items, itemSize, contentPadding.x) : setProp('height', items, itemSize, contentPadding.y);
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}
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}
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},
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setContentPosition(pos) {
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if (this.content) {
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const isBoth = this.isBoth();
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const isHorizontal = this.isHorizontal();
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const content = this.content;
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const first = pos ? pos.first : this.first;
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const itemSize = this.itemSize;
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const calculateTranslateVal = (_first, _size) => (_first * _size);
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const setTransform = (_x = 0, _y = 0) => content.style.transform = `translate3d(${_x}px, ${_y}px, 0)`;
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if (isBoth) {
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setTransform(calculateTranslateVal(first.cols, itemSize[1]), calculateTranslateVal(first.rows, itemSize[0]));
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}
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else {
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const translateVal = calculateTranslateVal(first, itemSize);
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isHorizontal ? setTransform(translateVal, 0) : setTransform(0, translateVal);
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}
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}
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},
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onScrollPositionChange(event) {
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const target = event.target;
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const isBoth = this.isBoth();
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const isHorizontal = this.isHorizontal();
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const itemSize = this.itemSize;
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const contentPadding = this.getContentPadding();
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const calculateScrollPos = (_pos, _padding) => _pos ? (_pos > _padding ? _pos - _padding : _pos) : 0;
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const calculateCurrentIndex = (_pos, _size) => Math.floor(_pos / (_size || _pos));
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const calculateTriggerIndex = (_currentIndex, _first, _last, _num, _isScrollDownOrRight) => {
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return (_currentIndex <= this.d_numToleratedItems ? this.d_numToleratedItems : (_isScrollDownOrRight ? (_last - _num - this.d_numToleratedItems) : (_first + this.d_numToleratedItems - 1)))
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};
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const calculateFirst = (_currentIndex, _triggerIndex, _first, _last, _num, _isScrollDownOrRight) => {
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if (_currentIndex <= this.d_numToleratedItems)
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return 0;
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else
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return _isScrollDownOrRight ?
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(_currentIndex < _triggerIndex ? _first : _currentIndex - this.d_numToleratedItems) :
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(_currentIndex > _triggerIndex ? _first : _currentIndex - (2 * this.d_numToleratedItems));
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};
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const calculateLast = (_currentIndex, _first, _last, _num, _isCols) => {
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let lastValue = _first + _num + (2 * this.d_numToleratedItems);
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if (_currentIndex >= this.d_numToleratedItems) {
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lastValue += (this.d_numToleratedItems + 1);
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}
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return this.getLast(lastValue, _isCols);
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};
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const scrollTop = calculateScrollPos(target.scrollTop, contentPadding.top);
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const scrollLeft = calculateScrollPos(target.scrollLeft, contentPadding.left);
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let newFirst = 0;
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let newLast = this.last;
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let isRangeChanged = false;
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if (isBoth) {
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const isScrollDown = this.lastScrollPos.top <= scrollTop;
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const isScrollRight = this.lastScrollPos.left <= scrollLeft;
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const currentIndex = { rows: calculateCurrentIndex(scrollTop, itemSize[0]), cols: calculateCurrentIndex(scrollLeft, itemSize[1]) };
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const triggerIndex = {
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rows: calculateTriggerIndex(currentIndex.rows, this.first.rows, this.last.rows, this.numItemsInViewport.rows, isScrollDown),
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cols: calculateTriggerIndex(currentIndex.cols, this.first.cols, this.last.cols, this.numItemsInViewport.cols, isScrollRight)
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};
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newFirst = {
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rows: calculateFirst(currentIndex.rows, triggerIndex.rows, this.first.rows, this.last.rows, this.numItemsInViewport.rows, isScrollDown),
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cols: calculateFirst(currentIndex.cols, triggerIndex.cols, this.first.cols, this.last.cols, this.numItemsInViewport.cols, isScrollRight)
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};
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newLast = {
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rows: calculateLast(currentIndex.rows, newFirst.rows, this.last.rows, this.numItemsInViewport.rows),
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cols: calculateLast(currentIndex.cols, newFirst.cols, this.last.cols, this.numItemsInViewport.cols, true)
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};
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isRangeChanged = (newFirst.rows !== this.first.rows || newFirst.cols !== this.first.cols) || (newLast.rows !== this.last.rows || newLast.cols !== this.last.cols);
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this.lastScrollPos = { top: scrollTop, left: scrollLeft };
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}
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else {
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const scrollPos = isHorizontal ? scrollLeft : scrollTop;
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const isScrollDownOrRight = this.lastScrollPos <= scrollPos;
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const currentIndex = calculateCurrentIndex(scrollPos, itemSize);
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const triggerIndex = calculateTriggerIndex(currentIndex, this.first, this.last, this.numItemsInViewport, isScrollDownOrRight);
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newFirst = calculateFirst(currentIndex, triggerIndex, this.first, this.last, this.numItemsInViewport, isScrollDownOrRight);
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newLast = calculateLast(currentIndex, newFirst, this.last, this.numItemsInViewport);
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isRangeChanged = newFirst !== this.first || newLast !== this.last;
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this.lastScrollPos = scrollPos;
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}
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return {
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first: newFirst,
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last: newLast,
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isRangeChanged
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}
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},
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onScrollChange(event) {
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const { first, last, isRangeChanged } = this.onScrollPositionChange(event);
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if (isRangeChanged) {
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const newState = { first, last };
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this.setContentPosition(newState);
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if (this.lazy) {
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this.$emit('lazy-load', { first, last });
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}
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this.first = first;
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this.last = last;
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this.$emit('scroll-index-change', { first, last });
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}
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},
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onScroll(event) {
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if (this.delay && !this.lazy) {
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if (this.scrollTimeout) {
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clearTimeout(this.scrollTimeout);
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}
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if (!this.d_loading && this.showLoader) {
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const { isRangeChanged: changed } = this.onScrollPositionChange(event);
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if (changed) {
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this.d_loading = true;
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}
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}
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this.scrollTimeout = setTimeout(() => {
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this.onScrollChange(event);
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if (this.d_loading && this.showLoader && !this.lazy) {
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this.d_loading = false;
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}
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}, this.delay);
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}
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else {
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this.onScrollChange(event);
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}
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},
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getOptions(renderedIndex) {
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let count = this.items.length;
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let index = this.isBoth() ? this.first.rows + renderedIndex : this.first + renderedIndex;
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return {
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index,
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count,
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first: index === 0,
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last: index === (count - 1),
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even: index % 2 === 0,
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odd: index % 2 !== 0
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};
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},
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getLoaderOptions(index) {
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let count = this.loaderArr.length;
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return {
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loading: this.d_loading,
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first: index === 0,
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last: index === (count - 1),
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even: index % 2 === 0,
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odd: index % 2 !== 0
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}
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},
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isHorizontal() {
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return this.orientation === 'horizontal';
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},
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isBoth() {
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return this.orientation === 'both';
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},
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scrollTo(options) {
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if (this.element) {
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this.element.scrollTo(options);
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}
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|
|
},
|
||
|
|
scrollToIndex(index, behavior = 'auto') {
|
||
|
|
const isBoth = this.isBoth();
|
||
|
|
const isHorizontal = this.isHorizontal();
|
||
|
|
const itemSize = this.itemSize;
|
||
|
|
const contentPadding = this.getContentPadding();
|
||
|
|
const calculateFirst = (_index = 0) => (_index <= this.d_numToleratedItems ? 0 : _index);
|
||
|
|
const calculateCoord = (_first, _size, _padding) => (_first * _size) + _padding;
|
||
|
|
const scrollTo = (left = 0, top = 0) => this.scrollTo({ left, top, behavior });
|
||
|
|
|
||
|
|
if (isBoth) {
|
||
|
|
const newFirst = { rows: calculateFirst(index[0]), cols: calculateFirst(index[1]) };
|
||
|
|
if (newFirst.rows !== this.first.rows || newFirst.cols !== this.first.cols)
|
||
|
|
scrollTo(calculateCoord(newFirst.cols, itemSize[1], contentPadding.left),calculateCoord(newFirst.rows, itemSize[0], contentPadding.top));
|
||
|
|
}
|
||
|
|
else {
|
||
|
|
const newFirst = calculateFirst(index);
|
||
|
|
|
||
|
|
if (newFirst !== this.first) {
|
||
|
|
isHorizontal ? scrollTo(calculateCoord(newFirst, itemSize, contentPadding.left), 0) : scrollTo(0, calculateCoord(newFirst, itemSize, contentPadding.top));
|
||
|
|
}
|
||
|
|
|
||
|
|
this.first = newFirst.index;
|
||
|
|
}
|
||
|
|
},
|
||
|
|
scrollInView(index, to, behavior = 'auto') {
|
||
|
|
if (to) {
|
||
|
|
const isBoth = this.isBoth();
|
||
|
|
const isHorizontal = this.isHorizontal();
|
||
|
|
const { first, viewport } = this.getRenderedRange();
|
||
|
|
const itemSize = this.itemSize;
|
||
|
|
const scrollTo = (left = 0, top = 0) => this.scrollTo({ left, top, behavior });
|
||
|
|
const isToStart = to === 'to-start';
|
||
|
|
const isToEnd = to === 'to-end';
|
||
|
|
|
||
|
|
if (isToStart) {
|
||
|
|
if (isBoth) {
|
||
|
|
if (viewport.first.rows - first.rows > index[0]) {
|
||
|
|
scrollTo(viewport.first.cols * itemSize[1], (viewport.first.rows - 1) * itemSize[0]);
|
||
|
|
}
|
||
|
|
else if (viewport.first.cols - first.cols > index[1]) {
|
||
|
|
scrollTo((viewport.first.cols - 1) * itemSize[1], viewport.first.rows * itemSize[0]);
|
||
|
|
}
|
||
|
|
}
|
||
|
|
else {
|
||
|
|
if (viewport.first - first > index) {
|
||
|
|
const pos = (viewport.first - 1) * itemSize;
|
||
|
|
isHorizontal ? scrollTo(pos, 0) : scrollTo(0, pos);
|
||
|
|
}
|
||
|
|
}
|
||
|
|
}
|
||
|
|
else if (isToEnd) {
|
||
|
|
if (isBoth) {
|
||
|
|
if (viewport.last.rows - first.rows <= index[0] + 1) {
|
||
|
|
scrollTo(viewport.first.cols * itemSize[1], (viewport.first.rows + 1) * itemSize[0]);
|
||
|
|
}
|
||
|
|
else if (viewport.last.cols - first.cols <= index[1] + 1) {
|
||
|
|
scrollTo((viewport.first.cols + 1) * itemSize[1], viewport.first.rows * itemSize[0]);
|
||
|
|
}
|
||
|
|
}
|
||
|
|
else {
|
||
|
|
if (viewport.last - first <= index + 1) {
|
||
|
|
const pos = (viewport.first + 1) * itemSize;
|
||
|
|
isHorizontal ? scrollTo(pos, 0) : scrollTo(0, pos);
|
||
|
|
}
|
||
|
|
}
|
||
|
|
}
|
||
|
|
}
|
||
|
|
else {
|
||
|
|
this.scrollToIndex(index, behavior);
|
||
|
|
}
|
||
|
|
},
|
||
|
|
getRenderedRange() {
|
||
|
|
const isBoth = this.isBoth();
|
||
|
|
const isHorizontal = this.isHorizontal();
|
||
|
|
const itemSize = this.itemSize;
|
||
|
|
const calculateFirstInViewport = (_pos, _size) => Math.floor(_pos / (_size || _pos));
|
||
|
|
|
||
|
|
let firstInViewport = this.first;
|
||
|
|
let lastInViewport = 0;
|
||
|
|
|
||
|
|
if (this.element) {
|
||
|
|
const scrollTop = this.element.scrollTop;
|
||
|
|
const scrollLeft = this.element.scrollLeft;
|
||
|
|
|
||
|
|
if (isBoth) {
|
||
|
|
firstInViewport = { rows: calculateFirstInViewport(scrollTop, itemSize[0]), cols: calculateFirstInViewport(scrollLeft, itemSize[1]) };
|
||
|
|
lastInViewport = { rows: firstInViewport.rows + this.numItemsInViewport.rows, cols: firstInViewport.cols + this.numItemsInViewport.cols };
|
||
|
|
}
|
||
|
|
else {
|
||
|
|
const scrollPos = isHorizontal ? scrollLeft : scrollTop;
|
||
|
|
firstInViewport = calculateFirstInViewport(scrollPos, itemSize);
|
||
|
|
lastInViewport = firstInViewport + this.numItemsInViewport;
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
return {
|
||
|
|
first: this.first,
|
||
|
|
last: this.last,
|
||
|
|
viewport: {
|
||
|
|
first: firstInViewport,
|
||
|
|
last: lastInViewport
|
||
|
|
}
|
||
|
|
};
|
||
|
|
},
|
||
|
|
elementRef(el) {
|
||
|
|
this.element = el;
|
||
|
|
},
|
||
|
|
contentRef(el) {
|
||
|
|
this.content = el;
|
||
|
|
},
|
||
|
|
spacerRef(el) {
|
||
|
|
this.spacer = el;
|
||
|
|
},
|
||
|
|
},
|
||
|
|
computed: {
|
||
|
|
containerClass() {
|
||
|
|
return ['p-virtualscroller', {
|
||
|
|
'p-both-scroll': this.isBoth(),
|
||
|
|
'p-horizontal-scroll': this.isHorizontal()
|
||
|
|
}, this.class];
|
||
|
|
},
|
||
|
|
loaderClass() {
|
||
|
|
return ['p-virtualscroller-loader', {
|
||
|
|
'p-component-overlay': !this.$slots.loader
|
||
|
|
}];
|
||
|
|
},
|
||
|
|
renderItems() {
|
||
|
|
const items = this.items;
|
||
|
|
if (items && !this.d_loading) {
|
||
|
|
const isBoth = this.isBoth();
|
||
|
|
|
||
|
|
if (isBoth) {
|
||
|
|
return items.slice(this.first.rows, this.last.rows).map((item) => {
|
||
|
|
const items = item.slice(this.first.cols, this.last.cols);
|
||
|
|
return items;
|
||
|
|
});
|
||
|
|
}
|
||
|
|
else {
|
||
|
|
return items.slice(this.first, this.last).map((item) => {
|
||
|
|
return item;
|
||
|
|
});
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
return null;
|
||
|
|
}
|
||
|
|
}
|
||
|
|
}
|
||
|
|
</script>
|
||
|
|
|
||
|
|
<style>
|
||
|
|
.p-virtualscroller {
|
||
|
|
position: relative;
|
||
|
|
overflow: auto;
|
||
|
|
contain: strict;
|
||
|
|
transform: translateZ(0);
|
||
|
|
will-change: scroll-position;
|
||
|
|
}
|
||
|
|
|
||
|
|
.p-virtualscroller-content {
|
||
|
|
position: absolute;
|
||
|
|
top: 0;
|
||
|
|
left: 0;
|
||
|
|
contain: content;
|
||
|
|
min-height: 100%;
|
||
|
|
min-width: 100%;
|
||
|
|
will-change: transform;
|
||
|
|
}
|
||
|
|
|
||
|
|
.p-virtualscroller-spacer {
|
||
|
|
position: absolute;
|
||
|
|
top: 0;
|
||
|
|
left: 0;
|
||
|
|
height: 1px;
|
||
|
|
width: 1px;
|
||
|
|
transform-origin: 0 0;
|
||
|
|
pointer-events: none;
|
||
|
|
}
|
||
|
|
|
||
|
|
.p-virtualscroller .p-virtualscroller-loader {
|
||
|
|
position: sticky;
|
||
|
|
top: 0;
|
||
|
|
left: 0;
|
||
|
|
width: 100%;
|
||
|
|
height: 100%;
|
||
|
|
}
|
||
|
|
|
||
|
|
.p-virtualscroller-loader.p-component-overlay {
|
||
|
|
display: flex;
|
||
|
|
align-items: center;
|
||
|
|
justify-content: center;
|
||
|
|
}
|
||
|
|
</style>
|