You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
43 lines
1.5 KiB
43 lines
1.5 KiB
import {KoArray} from 'app/client/lib/koArray';
|
|
import {IDisposableOwnerT, MutableObsArray, ObsArray, setDisposeOwner} from 'grainjs';
|
|
|
|
/**
|
|
* Returns a grainjs ObsArray that reflects the given koArray, mapping small changes using
|
|
* similarly efficient events.
|
|
*
|
|
* (Note that for both ObsArray and koArray, the main purpose in life is to be more efficient than
|
|
* an array-valued observable by handling small changes more efficiently.)
|
|
*/
|
|
export function createObsArray<T>(
|
|
owner: IDisposableOwnerT<ObsArray<T>> | null,
|
|
koArray: KoArray<T>,
|
|
): ObsArray<T> {
|
|
return setDisposeOwner(owner, new KoWrapObsArray(koArray));
|
|
}
|
|
|
|
|
|
/**
|
|
* An Observable that wraps a Knockout observable, created via fromKo(). It keeps minimal overhead
|
|
* when unused by only subscribing to the wrapped observable while it itself has subscriptions.
|
|
*
|
|
* This way, when unused, the only reference is from the wrapper to the wrapped object. KoWrapObs
|
|
* should not be disposed; its lifetime is tied to that of the wrapped object.
|
|
*/
|
|
class KoWrapObsArray<T> extends MutableObsArray<T> {
|
|
private _koSub: any = null;
|
|
|
|
constructor(_koArray: KoArray<T>) {
|
|
super(Array.from(_koArray.peek()));
|
|
|
|
this._koSub = _koArray.subscribe((splice: any) => {
|
|
const newValues = splice.array.slice(splice.start, splice.start + splice.added);
|
|
this.splice(splice.start, splice.deleted.length, ...newValues);
|
|
}, null, 'spliceChange');
|
|
}
|
|
|
|
public dispose(): void {
|
|
this._koSub.dispose();
|
|
super.dispose();
|
|
}
|
|
}
|