vscroll/dist/bundles/vscroll.umd.min.js

Virtual scroll engine

/**
 * vscroll (UMD)  by Denis Hilt | https://github.com/dhilt/vscroll | 2025-04-20T17:47:13.413Z | MIT license
 */

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Nt.doUpdate(e,l),c},n.removeVirtualItems=function(t,i){var r=i.indexes,o=i.increase;if(!r||!r.length)return!1;for(var s=t.buffer,a=t.viewport,c=t.state.fetch,l=s.finiteAbsMinIndex,u=s.firstIndex,f=s.finiteAbsMaxIndex,d=s.lastIndex,p=[],h=0,g=r.length;h<g;h++){if((v=r[h])>=l&&!isNaN(u)&&v<u)p.push(v);else{if(!(v<=f&&!isNaN(d)&&v>d))continue;p.push(v)}}if(!p.length)return!1;if(isNaN(c.firstVisible.index)){var m=a.getEdgeVisibleItem(s.items,e.Direction.backward),v=m.index,x=m.diff;c.firstVisible.index=v,isNaN(v)||(c.firstVisible.delta=-s.getSizeByIndex(v)+x)}return t.logger.log((function(){return"going to remove ".concat(p.length," item(s) virtually")})),s.removeVirtually(p,!!o),s.checkDefaultSize(),n.shiftFirstVisibleIndex(t,p,!!o),!0},n.shiftFirstVisibleIndex=function(e,t,i){var n=e.state.fetch.firstVisible;if(!isNaN(n.index)){var r=t.reduce((function(e,t){return e+(i&&t>n.index||!i&&t<n.index?1:0)}),0);n.index=n.index+(i?r:-r)}},n}(bt(he.remove)),$t=function(e){function t(){return null!==e&&e.apply(this,arguments)||this}return i(t,e),t.run=function(e,i){var n=t.parseInput(e,i).params;e.state.clip.forceForward=!(n&&n.backwardOnly),e.state.clip.forceBackward=!(n&&n.forwardOnly),e.workflow.call({process:t.process,status:ge.next})},t}(bt(he.clip)),At=function(e){function t(){return null!==e&&e.apply(this,arguments)||this}return i(t,e),t.run=function(e,i){var n=t.parseInput(e,i).params;if(n){var r=t.doReplace(e,n);e.workflow.call({process:t.process,status:r?ge.next:ge.done})}},t.doReplace=function(e,t){var i=e.buffer.items.filter((function(e){return t.predicate(e)})).map((function(e){return e.$index}));if(!i.length)return e.logger.log("no items to be replaced"),!1;var n=!1,r={predicate:function(e){var r=e.$index;return!i.includes(r)||!n&&(n=!0,t.items)},fixRight:t.fixRight};return Nt.doUpdate(e,r)},t}(bt(he.replace)),Dt=function(e){function t(){return null!==e&&e.apply(this,arguments)||this}return i(t,e),t.run=function(e,t){if(!!!(null==t?void 0:t.resume)&&!e.state.paused.get())return e.logger.log("pause scroller"),e.state.paused.set(!0),void e.workflow.call({process:he.pause,status:ge.done});e.logger.log("resume scroller"),e.state.paused.set(!1),e.workflow.call({process:he.pause,status:ge.next})},t}(bt(he.pause)),Rt=ft[he.fix],Ct=function(e){function t(){return null!==e&&e.apply(this,arguments)||this}return i(t,e),t.run=function(e,i){var n=e.workflow,r=t.parseInput(e,i),s=r.data;r.params&&(Object.entries(s.params).forEach((function(i){var n=o(i,2),r=n[0],a=n[1];a.isSet&&a.isValid&&t.runByType(e,r,a.value,s)})),n.call({process:t.process,status:ge.done}))},t.runByType=function(e,i,n,r){switch(i){case Rt.scrollPosition:return t.setScrollPosition(e,n);case Rt.minIndex:return t.setMinIndex(e,n);case Rt.maxIndex:return t.setMaxIndex(e,n);case Rt.updater:return t.updateItems(e,n);case Rt.scrollToItem:if(r.params){var o=r.params[Rt.scrollToItemOpt],s=o?o.value:void 0;return t.scrollToItem(e,n,s)}return;case Rt.scrollToItemOpt:return}},t.setScrollPosition=function(e,t){var i=e.viewport,n=t;t===-1/0?n=0:t===1/0&&(n=i.getScrollableSize()),i.setPosition(n)},t.setMinIndex=function(e,t){var i=e.buffer;e.settings.minIndex=t,i.absMinIndex=t},t.setMaxIndex=function(e,t){var i=e.buffer;e.settings.maxIndex=t,i.absMaxIndex=t},t.updateItems=function(e,t){var i=e.buffer,n=e.logger,r=!1,a=function(){return r=!0};i.items.forEach((function(e){return t(e.get(),a)})),r&&(n.log((function(){return"update Buffer.items reference"})),i.items=s([],o(i.items),!1))},t.scrollToItem=function(e,t,i){var n=e.buffer.items.find((function(e){return t(e.get())}));n?n.scrollTo(i):e.logger.log((function(){return"scrollToItem cancelled, item not found"}))},t}(bt(he.fix)),Tt=function(e){function t(){return null!==e&&e.apply(this,arguments)||this}return i(t,e),t.run=function(e){var i=e.state.startInnerLoop();e.workflow.call({process:t.process,status:ge.next,payload:i})},t}(yt(pe.start)),jt=function(t){function n(){return null!==t&&t.apply(this,arguments)||this}return i(n,t),n.run=function(e){var t=e.workflow,i=e.buffer,r=e.state,o=r.fetch,s=r.cycle;o.minIndex=i.minIndex,n.setPositionsAndIndexes(e),n.skipBufferedItems(e),e.settings.infinite&&n.checkBufferGaps(e),n.checkFetchPackSize(e),n.setFetchDirection(e),t.call({process:n.process,status:n.getStatus(e),payload:{process:s.initiator}})},n.setPositionsAndIndexes=function(e){n.setPositions(e),n.setFirstIndex(e),n.setLastIndex(e),e.logger.fetch()},n.setPositions=function(e){var t=e.state.fetch.positions,i=e.viewport,r=i.getBufferPadding();t.before=i.scrollPosition,t.startDelta=n.getStartDelta(e),t.relative=t.before-t.startDelta,t.start=t.relative-r,t.end=t.relative+i.getSize()+r},n.getStartDelta=function(e){var t=e.buffer,i=e.viewport.offset,n=0;if(i&&(n+=i),!t.defaultSize)return n;for(var r=t.finiteAbsMinIndex;r<t.startIndex;r++)n+=t.getSizeByIndex(r);return e.logger.log((function(){return s(["start delta is ".concat(n)],o(i?[" (+".concat(i," offset)")]:[]),!1)})),n},n.setFirstIndex=function(e){var t=e.state,i=e.buffer,n=t.fetch,r=n.positions.start,o=n.first,s=i.startIndex,a=0;if(t.cycle.innerLoop.isInitial)e.logger.log("skipping fetch backward direction [initial loop]");else if(i.defaultSize)for(var c=a,l=s;;){if(r>=0){var u=i.getSizeByIndex(l);if(c+u-r>0){s=l,a=c;break}if(c+=u,++l<i.absMinIndex)break}if(r<0){if(--l<i.absMinIndex)break;if(s=l,a=c-=i.getSizeByIndex(l),c-r<=0)break}}else e.logger.log("skipping fetch backward direction [no item size]");o.index=o.indexBuffer=Math.max(s,i.absMinIndex),o.position=a},n.setLastIndex=function(e){var t,i=e.state,n=i.fetch,r=i.cycle,o=e.buffer,s=e.settings,a=n.firstVisible,c=n.positions,l=c.relative,u=c.end,f=n.first,d=n.last;if(o.defaultSize){var p=f.indexBuffer,h=f.position;for(t=p;;){t=p;var g=o.getSizeByIndex(p);if(h+=g,isNaN(a.index)&&h>l&&(a.index=p,r.innerLoop.isInitial||(a.delta=h-g-l)),h>=u)break;if(p++>o.absMaxIndex)break}}else t=o.startIndex+s.bufferSize-1,e.logger.log("forcing fetch forward direction [no item size]");d.index=d.indexBuffer=Math.min(t,o.absMaxIndex)},n.skipBufferedItems=function(e){var t=e.buffer;if(t.size){for(var i=e.state.fetch,n=i.first.index,r=i.last.index,o=[[]],s=0,a=n;a<=r;a++)t.get(a)?o[s].length&&(o[++s]=[]):o[s].push(a);var c=o[0];o[0].length&&o[1]&&o[1].length&&(i.hasAnotherPack=!0,o[1].length>=o[0].length&&(c=o[1])),i.first.index=Math.max(c[0],t.absMinIndex),i.last.index=Math.min(c[c.length-1],t.absMaxIndex),i.first.index===n&&i.last.index===r||e.logger.fetch("after Buffer flushing")}},n.checkBufferGaps=function(e){var t=e.buffer,i=e.state.fetch;if(t.size){var n=i.first.index,r=t.lastIndex;n>r&&(i.first.index=i.first.indexBuffer=r+1);var o=t.firstIndex,s=i.last.index;s<o&&(i.last.index=i.last.indexBuffer=o-1),i.first.index===n&&i.last.index===s||e.logger.fetch("after Buffer filling (no clip case)")}},n.checkFetchPackSize=function(e){var t=e.buffer,i=e.state.fetch;if(i.shouldFetch){var r=i.first.index,o=i.last.index,s=e.settings.bufferSize-(o-r+1);if(!(s<=0)){if(!t.size||o>t.items[0].$index){var a=Math.min(o+s,t.absMaxIndex);a>o&&(i.last.index=i.last.indexBuffer=a)}else{var c=Math.max(r-s,t.absMinIndex);c<r&&(i.first.index=i.first.indexBuffer=c)}i.first.index===r&&i.last.index===o||(e.logger.fetch("after bufferSize adjustment"),n.skipBufferedItems(e))}}},n.setFetchDirection=function(t){var i=t.buffer,n=t.state.fetch;if(n.last.index){var r=e.Direction.forward;i.size&&(r=n.last.index<i.items[0].$index?e.Direction.backward:e.Direction.forward),n.direction=r,t.logger.log((function(){return'fetch direction is "'.concat(r,'"')}))}},n.getStatus=function(e){var t=e.state,i=t.cycle,n=t.fetch;return i.initiator===he.clip?(e.logger.log((function(){return'going to skip fetch due to "'.concat(he.clip,'" process')})),ge.next):n.shouldFetch?(e.logger.log((function(){return"going to fetch ".concat(n.count," items started from index ").concat(n.index)})),ge.next):ge.done},n}(yt(pe.preFetch)),Ft=function(e){function t(){return null!==e&&e.apply(this,arguments)||this}return i(t,e),t.run=function(e){var i=e.workflow,n={success:function(n){e.logger.log((function(){return"resolved ".concat(n.length," items ")+"(index = ".concat(e.state.fetch.index,", count = ").concat(e.state.fetch.count,")")})),e.state.fetch.newItemsData=n,i.call({process:t.process,status:ge.next})},fail:function(e){return i.call({process:t.process,status:ge.error,payload:{error:e}})}},r=t.get(e);t.complete(e,n,r)},t.complete=function(e,t,i){if(Object.prototype.hasOwnProperty.call(i,"data")){var n=i,r=n.data,o=n.error;n.isError?t.fail(o):t.success(r||[])}else{var s=e.state,a=s.scroll,c=s.fetch,l=e.viewport;null===a.positionBeforeAsync&&(a.positionBeforeAsync=l.scrollPosition),c.cancel=function(){t.success=function(){return null},t.fail=function(){return null}},i.then((function(e){return t.success(e)}),(function(e){return t.fail(e)}))}},t.get=function(e){var t,i,n,r,o=e.datasource.get,s=e.state.fetch,a=function(e){n?n(e):t=e||null},c=function(e){r?r(e):i=e||null},l=o(s.index,s.count,a,c);if(l&&"object"==typeof l&&null!==l){if("function"==typeof l.then)return l;if("function"==typeof l.subscribe){var u=void 0;u=l.subscribe(a,c,(function(){u&&"object"==typeof u&&"function"==typeof u.unsubscribe&&u.unsubscribe()}))}}return t||i?{data:i?null:t||[],error:i,isError:!!i}:new Promise((function(e,t){n=e,r=t}))},t}(yt(pe.fetch)),Bt=function(e){function t(){return null!==e&&e.apply(this,arguments)||this}return i(t,e),t.run=function(e){var i=e.workflow;t.setItems(e)?(t.setBufferLimits(e),i.call({process:t.process,status:e.state.fetch.hasNewItems?ge.next:ge.done})):i.call({process:t.process,status:ge.error,payload:{error:"Can't set buffer items"}})},t.setBufferLimits=function(e){var t=e.buffer,i=e.state,n=i.fetch,r=i.cycle.innerLoop,o=n.items,s=n.first.index,a=n.last.index;if(o.length){var c=o.length-1;s<o[0].$index&&(t.absMinIndex=o[0].$index),a>o[c].$index&&(t.absMaxIndex=o[c].$index)}else(a<t.minIndex||r.isInitial)&&(t.absMinIndex=t.minIndex),(s>t.maxIndex||r.isInitial)&&(t.absMaxIndex=t.maxIndex)},t.setItems=function(e){var t=e.buffer,i=e.state,n=i.fetch,r=i.cycle,o=n.newItemsData;if(!o||!o.length)return!0;var s=n.index;return o.length<n.count&&(r.innerLoop.isInitial?s=t.startIndex:n.first.index<t.minIndex&&(s=t.firstIndex-o.length)),n.items=o.map((function(t,i){return new Et(s+i,t,e.routines)})),t.setItems(n.items)},t}(yt(pe.postFetch)),Lt=function(e){function t(){return null!==e&&e.apply(this,arguments)||this}return i(t,e),t.run=function(e){var i=e.workflow,n=e.state,r=n.cycle,o=n.render,s=n.scroll,a=n.fetch,c=e.viewport,l=e.routines;e.logger.stat("before new items render"),null===s.positionBeforeAsync&&(s.positionBeforeAsync=c.scrollPosition),o.cancel=l.render((function(){o.cancel=null,t.doRender(e)?i.call({process:t.process,status:o.noSize?ge.done:ge.next,payload:{process:r.initiator}}):i.call({process:t.process,status:ge.error,payload:{error:"Can't associate item with element"}})}),{items:a.items.map((function(e){return e.get()}))})},t.doRender=function(e){var i=e.state,n=i.fetch,r=i.render,o=e.viewport,s=e.buffer,a=e.logger;return r.positionBefore=o.scrollPosition,!(!n.isCheck&&(r.sizeBefore=o.getScrollableSize(),!n.items.every((function(i){return t.processElement(e,i)}))))&&(s.checkDefaultSize(),r.sizeAfter=o.getScrollableSize(),a.stat("after new items render"),a.log((function(){return r.noSize?"viewport size has not been changed":void 0})),!0)},t.processElement=function(e,t){var i=e.viewport,n=e.buffer,r=i.findItemElementById(t.nodeId);return!!r&&(t.element=r,t.makeVisible(),t.setSize(n.getSizeByIndex(t.$index)),n.cacheItem(t),!0)},t}(yt(pe.render)),_t=function(e){function t(){return null!==e&&e.apply(this,arguments)||this}return i(t,e),t.run=function(e,i){var r=(void 0===i?{}:i).error,o=e.workflow,s=e.state.cycle.interrupter;if(r||s||t.calculateParams(e),function(e){return!!e.call.interrupted}(o))o.call({process:t.process,status:ge.done});else{var a=t.shouldContinueRun(e,r);e.state.endInnerLoop(),o.call({process:t.process,status:a?ge.next:ge.done,payload:n({},s?{process:s}:{})})}},t.calculateParams=function(e){var t=e.adapter,i=e.workflow;t.setFirstOrLastVisible({first:!0,workflow:i}),t.setFirstOrLastVisible({last:!0,workflow:i})},t.shouldContinueRun=function(e,t){var i=e.state,n=i.cycle,r=i.fetch,o=i.render;return!!n.interrupter||!t&&(!(!r.simulate||!r.isCheck||o.noSize)||(!(!r.simulate||!r.doRemove)||!(r.simulate||!(r.hasNewItems&&!o.noSize||r.hasAnotherPack))))},t}(yt(pe.end)),Wt=function(e){function t(){return null!==e&&e.apply(this,arguments)||this}return i(t,e),t.run=function(e){var i=e.workflow,n=e.viewport,r=e.state.scroll;r.positionBeforeAdjust=n.scrollPosition,t.setPaddings(e),r.positionAfterAdjust=n.scrollPosition;var o=t.calculatePosition(e);t.setAdditionalForwardPadding(e,o),t.setPosition(e,o,(function(){return i.call({process:t.process,status:ge.done})}))},t.setPaddings=function(e){var t,i,n=e.viewport,r=e.buffer,o=e.settings.inverse,s=e.state.fetch,a=r.getFirstVisibleItem(),c=r.getLastVisibleItem();a&&c?(t=a.$index,i=c.$index):i=(t=isNaN(s.firstVisible.index)?r.startIndex:s.firstVisible.index)-1;var l,u=n.paddings,f=u.forward,d=u.backward,p=0,h=0;for(l=r.finiteAbsMinIndex;l<t;l++)p+=r.getSizeByIndex(l);for(l=i+1;l<=r.finiteAbsMaxIndex;l++)h+=r.getSizeByIndex(l);var g=p+(n.getScrollableSize()-f.size-d.size)+h,m=n.getSize()-g;m>0&&(o?p+=m:h+=m,e.logger.log((function(){return o?"backward":"forward"+" padding will be increased by ".concat(m," to fill the viewport")}))),d.size=p,f.size=h,e.logger.stat("after paddings adjustments")},t.calculatePosition=function(e){var t=e.viewport,i=e.buffer,n=e.state,r=n.fetch,o=n.render,s=n.scroll,a=t.paddings.backward.size;if(!isNaN(r.firstVisible.index)&&!isNaN(i.firstIndex)){e.logger.log("first index = ".concat(r.firstVisible.index,", delta = ").concat(r.firstVisible.delta));var c=r.shouldCheckPreSizeExpectation(i.lastIndex);i.items.forEach((function(e){e.$index<r.firstVisible.index?a+=e.size:(e.$index===r.firstVisible.index&&r.firstVisible.delta&&(a-=r.firstVisible.delta),c&&e.preSize&&r.items.includes(e)&&(a+=e.size-e.preSize))}))}if(null!==s.positionBeforeAsync){var l=o.positionBefore-s.positionBeforeAsync;0!==l&&(e.logger.log("shift position due to fetch-render difference (".concat(l,")")),a+=l)}return t.offset>0&&(a||r.positions.before)&&(a+=t.offset),Math.round(a)},t.setAdditionalForwardPadding=function(e,t){var i=e.viewport,n=e.buffer;if(e.state.cycle.isInitial&&_t.shouldContinueRun(e,null)){var r=t-i.getMaxScrollPosition();if(!(r<=0)){var o=n.getLastVisibleItem();if(o){for(var s=0,a=o.$index+1;s<=r&&a<=n.absMaxIndex;)s+=n.getSizeByIndex(a++);var c=Math.min(s,r);c&&(i.paddings.forward.size+=c,e.logger.log("increase fwd padding due to lack of items (".concat(r," -> ").concat(c,")")))}}}},t.setPosition=function(e,t,i){var n=e.state.scroll,r=e.viewport,o=e.routines;if(!n.hasPositionChanged(t))return i();n.syntheticPosition=t,n.syntheticFulfill=!1,n.cancelAnimation=o.animate((function(){n.cancelAnimation=null;var o=n.positionAfterAdjust-r.scrollPosition,s="";o>0&&(t-=o,n.syntheticPosition=t,s=" (-".concat(o,")")),n.syntheticFulfill=!0,r.scrollPosition=t,e.logger.stat("after scroll adjustment"+s),i()}))},t}(yt(pe.adjust)),Ut=function(t){function n(){return null!==t&&t.apply(this,arguments)||this}return i(n,t),n.run=function(e){n.prepareClip(e),e.workflow.call({process:n.process,status:ge.next,payload:{doClip:e.state.clip.doClip}})},n.prepareClip=function(t){var i=t.state,r=i.fetch,o=i.clip;if(!n.shouldNotClip(t)){var s=r.first.indexBuffer,a=r.last.indexBuffer;t.logger.log((function(){return"looking for ".concat(r.direction?"anti-"+r.direction+" ":"","items ")+"that are out of [".concat(s,"..").concat(a,"] range")})),n.isBackward(t,s)&&n.prepareClipByDirection(t,e.Direction.backward,s),n.isForward(t,a)&&n.prepareClipByDirection(t,e.Direction.forward,a),o.doClip||t.logger.log("skipping clip [no items to clip]")}},n.shouldNotClip=function(e){var t=e.settings,i=e.buffer,n=e.state;return t.infinite&&!n.clip.force?(e.logger.log("skipping clip [infinite mode]"),!0):i.size?!!n.cycle.isInitial&&(e.logger.log("skipping clip [initial cycle]"),!0):(e.logger.log("skipping clip [empty buffer]"),!0)},n.isBackward=function(t,i){var n=t.buffer,r=t.state,o=r.clip,s=r.fetch;return o.force?o.forceBackward:s.direction!==e.Direction.backward&&i-1>=n.absMinIndex},n.isForward=function(t,i){var n=t.buffer,r=t.state,o=r.clip,s=r.fetch;return o.force?o.forceForward:s.direction!==e.Direction.forward&&i+1<=n.absMaxIndex},n.prepareClipByDirection=function(t,i,n){var r=i===e.Direction.forward;t.buffer.items.forEach((function(e){(!r&&e.$index<n||r&&e.$index>n)&&(e.toRemove=!0,e.removeDirection=i,t.state.clip.doClip=!0)}))},n}(yt(pe.preClip)),qt=function(t){function n(){return null!==t&&t.apply(this,arguments)||this}return i(n,t),n.run=function(e){var t=e.workflow;n.doClip(e),t.call({process:n.process,status:ge.next})},n.doClip=function(t){var i,n=t.buffer,r=t.viewport.paddings,o=t.state.clip,s=t.logger,a=((i={})[e.Direction.backward]=0,i[e.Direction.forward]=0,i);s.stat("before clip (".concat(++o.callCount,")"