@progress/kendo-react-grid/VirtualScroll.js

React Data Grid (Table) provides 100+ ready-to-use data grid features. KendoReact Grid package

/**
 * @license
 *-------------------------------------------------------------------------------------------
 * Copyright © 2025 Progress Software Corporation. All rights reserved.
 * Licensed under commercial license. See LICENSE.md in the package root for more information
 *-------------------------------------------------------------------------------------------
 */
"use strict";Object.defineProperty(exports,Symbol.toStringTag,{value:"Module"});const p=require("react");function g(r){const i=Object.create(null,{[Symbol.toStringTag]:{value:"Module"}});if(r){for(const t in r)if(t!=="default"){const s=Object.getOwnPropertyDescriptor(r,t);Object.defineProperty(i,t,s.get?s:{enumerable:!0,get:()=>r[t]})}}return i.default=r,Object.freeze(i)}const u=g(p);class f{constructor(i){this.table=null,this.containerHeight=0,this.topCacheCount=0,this.attendedSkip=0,this.propsSkip=0,this.total=0,this.scrollableVirtual=!1,this.realSkip=0,this.pageSize=0,this.PageChange=null,this.tableBodyRef=null,this.fixedScroll=!1,this.askedSkip=void 0,this.containerRef=null,this.tableTransform="",this.prevScrollPos=0,this.tableTranslate=0,this.scrollSyncing=!1,this.reactVersion=Number.parseFloat(u.version),this.topItems=(t,s)=>{if(!this.container||s)return{topItemsCount:0,topItemsHeight:0};const l=this.container.clientHeight,e=Math.ceil(l/t[0].line),n=Math.ceil((t.length-e)/2);let o=0;for(let a=0;a<n;a++)o+=t[a].line+t[a].acc;return{topItemsCount:n,topItemsHeight:o,itemsNeededOnScreen:e+e/2}},this.horizontalScrollbarHeight=()=>this.container?this.container.offsetHeight-this.container.clientHeight:0,i&&(this.topCacheCount=4,this.attendedSkip=-this.topCacheCount),this.scrollHandler=this.scrollHandler.bind(this)}get container(){var i;return(i=this.containerRef)==null?void 0:i.current}get rowHeights(){var l,e;const i=[],t=((l=this.tableBodyRef)==null?void 0:l.current)&&((e=this.tableBodyRef)==null?void 0:e.current.children)||[];let s=0;for(let n=0;n<t.length;n++){if(t[n].className.indexOf("k-grouping-row")>-1){s+=t[n].scrollHeight;continue}t[n].className.indexOf("k-detail-row")>-1?i[i.length-1].line+=t[n].scrollHeight:(i.push({line:t[n].scrollHeight,acc:s}),s=0)}return i}changePage(i,t){this.attendedSkip=i-this.topCacheCount,this.PageChange&&this.PageChange({skip:Math.max(0,i-this.topCacheCount),take:this.pageSize},t)}translate(i,t){this.tableTranslate=i,this.scrollableVirtual&&this.table&&(this.reactVersion<=17||t?this.table.style.transform="translateY("+i+"px)":this.tableTransform="translateY("+i+"px)")}reset(){this.scrollSyncing=!0,!this.fixedScroll&&(this.container&&(this.container.scrollTop=0),this.translate(0,!0))}localScrollUp(i){if(!this.container)return;const t=this.rowHeights,s=this.container.scrollTop;let l=this.tableTranslate,e=0;const{topItemsCount:n,topItemsHeight:o,itemsNeededOnScreen:a}=this.topItems(t,!!this.topCacheCount),h=s-l;if(!(h>o||t.length<=a)){for(;e<this.topCacheCount+this.attendedSkip-this.realSkip+n&&this.propsSkip-e>0&&!(l+(t[t.length-1-e].line+t[t.length-1-e].acc)+h<=s);)l-=t[t.length-1-e].line+t[t.length-1-e].acc,e++;if(e===0&&this.topCacheCount===0&&this.attendedSkip>0&&(l=Math.max(l-t[0].line,0),e=1),this.propsSkip-e<=0&&l>s){this.translate(0),this.changePage(0,i),this.container.scrollTop=0;return}if(l>s&&(l=s),l!==this.tableTranslate){this.translate(Math.max(0,l-o));const c=Math.max(0,this.propsSkip-e-n);this.changePage(c,i)}}}localScrollDown(i){if(!this.container)return;const t=this.rowHeights,s=this.container.scrollTop;let l=this.tableTranslate,e=0;const{topItemsCount:n,topItemsHeight:o,itemsNeededOnScreen:a}=this.topItems(t,!!this.topCacheCount);for(;e<t.length-this.topCacheCount&&!(l+t[e].line+t[e].acc>s);)l+=t[e].line+t[e].acc,e++;n>this.propsSkip+e||t.length<=a||(e>=t.length-this.topCacheCount&&this.propsSkip+e>=this.total?(this.translate(l-o),this.changePage(this.total-1-n,i)):l!==this.tableTranslate&&this.propsSkip+e-n!==this.propsSkip&&(this.translate(l-o),this.changePage(this.propsSkip+e-n,i)))}scrollNonStrict(i){const t=this.total*this.prevScrollPos/this.containerHeight;let s=Math.floor(t);s>=this.total&&(s=this.total-1);const l=Math.min(t-s,1);let e=0;const n=s-this.propsSkip,o=this.rowHeights;n>=0&&n<=1?e=-((o[0].line+o[0].acc)*l):n===-1&&(e=-((o[o.length-1].line+o[o.length-1].acc)*l));const{topItemsCount:a,topItemsHeight:h}=this.topItems(o,!!this.topCacheCount);this.translate(Math.max(0,e-h-this.horizontalScrollbarHeight()+this.containerHeight*t/this.total)),this.changePage(s-a,i)}scrollHandler(i){if(!this.scrollableVirtual)return;if(this.scrollSyncing||!this.container||!this.table){this.scrollSyncing=!1;return}const t=this.container.scrollTop,s=this.prevScrollPos;if(this.prevScrollPos=t,this.askedSkip!==void 0){this.translate(this.containerHeight*this.askedSkip/this.total),this.changePage(this.askedSkip,i),this.prevScrollPos=t,this.askedSkip=void 0;return}t-s<0&&t>this.tableTranslate-this.table.scrollHeight/10?this.localScrollUp(i):t-s>0&&t<this.tableTranslate+this.table.scrollHeight*2/3?this.localScrollDown(i):this.scrollNonStrict(i),this.prevScrollPos=t}}exports.VirtualScroll=f;