Previous implementation would fire changes `QueryList.changes.subscribe`
whenever the `QueryList` was recomputed. This resulted in artificially
high number of change notifications, as it is possible that recomputing
`QueryList` results in the same list. When the `QueryList` gets recomputed
is an implementation detail and it should not be the thing which determines
how often change event should fire.
This change introduces a new `emitDistinctChangesOnly` option for
`ContentChildren` and `ViewChildren`.
```
export class QueryCompWithStrictChangeEmitParent {
@ContentChildren('foo', {
// This option will become the default in the future
emitDistinctChangesOnly: true,
})
foos!: QueryList<any>;
}
```
PR Close#40091
Previously we would write to class/style as strings `element.className` and `element.style.cssText`. Turns out that approach is good for initial render but not good for updates. Updates using this approach are problematic because we have to check to see if there was an out of bound write to style and than perform reconciliation. This also requires the browser to bring up CSS parser which is expensive.
Another problem with old approach is that we had to queue the DOM writes and flush them twice. Once on element advance instruction and once in `hostBindings`. The double flushing is expensive but it also means that a directive can observe that styles are not yet written (they are written after directive executes.)
The new approach uses `element.classList.add/remove` and `element.style.setProperty/removeProperty` API for updates only (it continues to use `element.className` and `element.style.cssText` for initial render as it is cheaper.) The other change is that the styling changes are applied immediately (no queueing). This means that it is the instruction which computes priority. In some circumstances it may result in intermediate writes which are than overwritten with new value. (This should be rare)
Overall this change deletes most of the previous code and replaces it with new simplified implement. The simplification results in code savings.
PR Close#34804
This change introduces several functions for manipulating items in an array in an efficient (binary search) way.
- `arraySplice` a faster version of `Array.splice()`.
- `arrayInsert` a faster version of `Array.splice(index, 0, value)`.
- `arrayInsert2` a faster version of `Array.splice(index, 0, value1, value2)`.
- `arrayInsertSorted` a way to insert a value into sorted list.
- `arrayRemoveSorted` a way to remove a value from a sorted list.
- `arrayIndexOfSorted` a way to find a value in a sorted list.
- `ArrayMap` Efficient implementation of `Map` as an `Array`.
- `arrayMapSet`, `arrayMapGet`, `arrayMapIndexOf`, and `arrayMapDelete` for manipulating `ArrayMap`s.
PR Close#34804
In View Engine, developers can pass bootstrap and entry components
as nested arrays. e.g.
```ts
export const MyOtherEntryComponents = [A, B, C]
@NgModule({
entryComponents: [MyComp, MyOtherEntryComponents]
})
```
Currently using nested arrays for these properties causes
unexpected errors to be reported in Ivy since the semantic
NgModule checks aren't properly recursing into the nested
entry/bootstrap components. This issue has been unveiled by
enabling the strict function parameter checks.
PR Close#30993
The `flatten` function used `concat` and `slice` which created a lot of intermediary
object allocations. Because `flatten` is used from query any benchmark which
used query would exhibit high minor GC counts.
PR Close#30468
This commit removes code duplication where we had 2 versions of a
`flatten` utility. Moreover this change results in queries using
a non-recursive version of `flatten` which should result in a better
performance of query refresh operations.
PR Close#29547
