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perf(virtual-scroll): fast path for removing

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This commit is contained in:
Manu Mtz.-Almeida
2017-04-23 16:00:04 +02:00
committed by Manuel Mtz-Almeida
parent 88e5642f60
commit 8baa6474a4
2 changed files with 22 additions and 16 deletions
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31
src/components/virtual-scroll/virtual-scroll.ts
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@ -233,7 +233,8 @@ export class VirtualScroll implements DoCheck, AfterContentInit, OnDestroy {
scrollTop: 0,
};
_queue: number = SCROLL_QUEUE_NO_CHANGES;
_recordSize: number = 0;
_virtualTrackBy: TrackByFn;
@ContentChild(VirtualItem) _itmTmp: VirtualItem;
@ -416,10 +417,7 @@ export class VirtualScroll implements DoCheck, AfterContentInit, OnDestroy {
*/
firstRecord(): number {
const cells = this._cells;
if (cells.length > 0) {
return cells[0].record;
}
return 0;
return (cells.length > 0) ? cells[0].record : 0;
}
/**
@ -427,10 +425,7 @@ export class VirtualScroll implements DoCheck, AfterContentInit, OnDestroy {
*/
lastRecord(): number {
const cells = this._cells;
if (cells.length > 0) {
return cells[cells.length - 1].record;
}
return 0;
return (cells.length > 0) ? cells[cells.length - 1].record : 0;
}
/**
@ -451,15 +446,25 @@ export class VirtualScroll implements DoCheck, AfterContentInit, OnDestroy {
let needClean = false;
if (changes) {
var lastRecord = this.lastRecord() + 1;
changes.forEachOperation((item, _, cindex) => {
if (item.previousIndex != null || (cindex < lastRecord)) {
changes.forEachOperation((_, pindex, cindex) => {
// add new record after current position
if (pindex === null && (cindex < lastRecord)) {
console.debug('adding record before current position, slow path');
needClean = true;
return;
}
// remove record after current position
if (pindex < lastRecord && cindex === null) {
console.debug('removing record before current position, slow path');
needClean = true;
return;
}
});
} else {
needClean = true;
}
this._recordSize = this._records.length;
this.readUpdate(needClean);
this.writeUpdate(needClean);
@ -555,7 +560,7 @@ export class VirtualScroll implements DoCheck, AfterContentInit, OnDestroy {
this._itmTmp.viewContainer,
this._itmTmp.templateRef,
this._hdrTmp && this._hdrTmp.templateRef,
this._ftrTmp && this._ftrTmp.templateRef, needClean,
this._ftrTmp && this._ftrTmp.templateRef, needClean
);
});