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June 18, 2020 06:56
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A small Vue component to render big array of items. It will not render invisible <tr> tags. This help increase performance.
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| READ AND REMOVE ME: Replace this.$store.state.blogs.data by your items array | |
| READ AND REMOVE ME: currentScrollPosition + 1000 mean only render from current position + 1000px, you can change as you want | |
| <template> | |
| <table class="table table-fixed"> | |
| <thead> | |
| <tr> | |
| <th scope="col">Content</th> | |
| </tr> | |
| </thead> | |
| <tbody :style="'min-height:'+minTableHeight+'px'"> | |
| <tr v-for="(item, index) in this.$store.state.blogs.data" :id="'item_no_'+index" | |
| :style="'height: '+getHeightOfTr(index)+'px'"> | |
| <template v-if="itemsPosition[index] >= currentScrollPosition && itemsPosition[index] < currentScrollPosition + 1000"> | |
| <td><strong>{{item.id}}</strong> {{item.content}}</td> | |
| </template> | |
| </tr> | |
| </tbody> | |
| </table> | |
| </template> | |
| <script> | |
| export default { | |
| name: 'table-virtual-scroller', | |
| data() { | |
| return { | |
| minRowHeight: 20, | |
| minTableHeight: 0, | |
| itemsHeight: {}, | |
| itemsPosition: {}, | |
| currentScrollPosition: 1, | |
| } | |
| }, | |
| methods: { | |
| getHeightOfTr(index) { | |
| return this.itemsHeight.hasOwnProperty(index) ? this.itemsHeight[index] : this.minRowHeight; | |
| }, | |
| saveHeightOfTr() { | |
| // Init | |
| let itemsHeightCopy = this.itemsHeight; | |
| let itemsPositionCopy = this.itemsPosition; | |
| let lastRowYPosition = 0; | |
| // Foreach | |
| for (let index in this.$store.state.blogs.data) { | |
| let elementExists = document.getElementById('item_no_' + index); | |
| let height = elementExists ? elementExists.offsetHeight : this.minRowHeight; | |
| lastRowYPosition += height; | |
| itemsHeightCopy[index] = height; | |
| itemsPositionCopy[index] = lastRowYPosition; | |
| } | |
| // Update state | |
| this.minTableHeight = lastRowYPosition; | |
| this.itemsHeight = itemsHeightCopy; | |
| this.itemsPosition = itemsPositionCopy; | |
| console.log(this.itemsHeight); | |
| }, | |
| checkScrollPosition(e = {}) { | |
| let el = this.$el; | |
| // Only catch my scroll, avoid parent 's scroller | |
| if ( | |
| (el.scrollTop === 0 && e.deltaY < 0) || | |
| (Math.abs(el.scrollTop - (el.scrollHeight - el.clientHeight)) <= 1 && | |
| e.deltaY > 0) | |
| ) { | |
| e.preventDefault(); | |
| } | |
| // | |
| this.updateWindow(e); | |
| }, | |
| updateWindow(e) { | |
| this.currentScrollPosition = this.$el.scrollTop; | |
| } | |
| }, | |
| updated() { | |
| // Re-calculate height of all tr | |
| this.saveHeightOfTr(); | |
| }, | |
| mounted() { | |
| // Listen for scroll event | |
| window.vscroll = this; | |
| this._checkScrollPosition = this.checkScrollPosition.bind(this); | |
| this.checkScrollPosition(); | |
| this.$el.addEventListener("scroll", this._checkScrollPosition); | |
| this.$el.addEventListener("wheel", this._checkScrollPosition); | |
| }, | |
| beforeDestroy() { | |
| this.$el.removeEventListener("scroll", this._checkScrollPosition); | |
| this.$el.removeEventListener("wheel", this._checkScrollPosition); | |
| }, | |
| } | |
| </script> | |
| <style scoped> | |
| table { | |
| display: block; | |
| height: 80vh !important; | |
| overflow-y: auto; | |
| } | |
| </style> |
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