store.ts
58 lines
| 2.0 KiB
| video/mp2t
|
TypeScriptLexer
cin
|
r116 | import { PromiseOrValue } from "@implab/core-amd/interfaces"; | ||
| import { isPromise } from "@implab/core-amd/safe"; | ||||
| import { observe, Observable } from "./observable"; | ||||
| export interface OrderedUpdate<T> { | ||||
| /** The item is being updated */ | ||||
| readonly item: T; | ||||
| /** The previous index of the item, -1 in case it is inserted */ | ||||
| readonly prevIndex: number; | ||||
| /** The new index of the item, -1 in case it is deleted */ | ||||
| readonly newIndex: number; | ||||
| } | ||||
| export type QueryResults<T> = Observable<OrderedUpdate<T>>; | ||||
| interface DjObservableResults<T> { | ||||
| /** | ||||
| * Allows observation of results | ||||
| */ | ||||
| observe(listener: (object: T, previousIndex: number, newIndex: number) => void, includeUpdates?: boolean): { | ||||
| remove(): void; | ||||
| }; | ||||
| } | ||||
| interface Queryable<T, A extends unknown[]> { | ||||
| query(...args: A): PromiseOrValue<T[]>; | ||||
| } | ||||
| export const isObservableResults = <T>(v: object): v is DjObservableResults<T> => | ||||
| v && (typeof (v as { observe?: unknown; }).observe === "function"); | ||||
| export const query = <T, A extends unknown[]>(store: Queryable<T, A>, includeUpdates = true) => | ||||
| (...args: A) => { | ||||
| return observe<OrderedUpdate<T>>(({ next, complete, error, isClosed }) => { | ||||
| try { | ||||
| const results = store.query(...args); | ||||
| if (isPromise(results)) { | ||||
| results.then(items => items.forEach((item, newIndex) => next({ item, newIndex, prevIndex: -1 }))) | ||||
| .then(undefined, error); | ||||
| } else { | ||||
| results.forEach((item, newIndex) => next({ item, newIndex, prevIndex: -1 })); | ||||
| } | ||||
| if (!isClosed() && isObservableResults<T>(results)) { | ||||
| const h = results.observe((item, prevIndex, newIndex) => next({ item, prevIndex, newIndex }), includeUpdates); | ||||
| return () => h.remove(); | ||||
| } else { | ||||
| complete(); | ||||
| } | ||||
| } catch (err) { | ||||
| error(err); | ||||
| } | ||||
| }); | ||||
| }; | ||||