|
|
import { PromiseOrValue } from "@implab/core-amd/interfaces";
|
|
|
import { isCancellable, isPromise } from "@implab/core-amd/safe";
|
|
|
import { observe, Observable, empty } from "./observable";
|
|
|
import { after } from "dojo/aspect";
|
|
|
import { subject } from "./operators/subject";
|
|
|
|
|
|
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, Q, O> {
|
|
|
query(query?: Q, options?: O): PromiseOrValue<T[]>;
|
|
|
}
|
|
|
|
|
|
export const isDjObservableResults = <T>(v: object): v is DjObservableResults<T> =>
|
|
|
v && (typeof (v as { observe?: unknown; }).observe === "function");
|
|
|
|
|
|
export const query = <T, Q, O>(store: Queryable<T, Q, O>, includeUpdates = true) =>
|
|
|
(query?: Q, options?: O & { observe?: boolean }) => {
|
|
|
return observe<OrderedUpdate<T>>(({ next, complete, error, isClosed }) => {
|
|
|
|
|
|
const processResults = (items: T[]) =>
|
|
|
items.forEach((item, newIndex) => next({ item, newIndex, prevIndex: -1 }));
|
|
|
|
|
|
try {
|
|
|
const results = store.query(query, options);
|
|
|
if (isPromise(results)) {
|
|
|
results.then(processResults).then(undefined, error);
|
|
|
} else {
|
|
|
processResults(results);
|
|
|
}
|
|
|
|
|
|
if (!isClosed() && (options?.observe !== false) && isDjObservableResults<T>(results)) {
|
|
|
const h = results.observe((item, prevIndex, newIndex) => next({ item, prevIndex, newIndex }), includeUpdates);
|
|
|
return () => h.remove();
|
|
|
} else {
|
|
|
complete();
|
|
|
}
|
|
|
} catch (err) {
|
|
|
error(err);
|
|
|
}
|
|
|
});
|
|
|
|
|
|
};
|
|
|
|
|
|
interface IndexedStore<T> {
|
|
|
get(id: string | number): PromiseLike<T> | T | null | undefined;
|
|
|
}
|
|
|
|
|
|
interface Notifications<T> {
|
|
|
notify(item: T | undefined, id: string | number | undefined): void;
|
|
|
}
|
|
|
|
|
|
const hasNotifications = <T>(x: unknown): x is Notifications<T> =>
|
|
|
typeof x === "object" && x !== null && (typeof (x as Notifications<T>).notify === "function");
|
|
|
|
|
|
interface GetOpts {
|
|
|
observe?: boolean;
|
|
|
}
|
|
|
|
|
|
type Change<T> = [item: NonNullable<T>, id: string | number | undefined] |
|
|
|
[item: undefined | null, id: string | number];
|
|
|
|
|
|
const filterItem = (itemId: string | number) =>
|
|
|
<T>(source: Observable<Change<T>>) =>
|
|
|
observe<T>(({ next, complete, error }) => {
|
|
|
const subscription = source
|
|
|
.filter(([, id]) => id === itemId)
|
|
|
.subscribe({
|
|
|
next: ([item]) => item !== null && item !== undefined ? next(item) : complete(),
|
|
|
complete,
|
|
|
error
|
|
|
});
|
|
|
return () => subscription.unsubscribe();
|
|
|
});
|
|
|
|
|
|
export const get = <T>(store: IndexedStore<T>) => {
|
|
|
const changes = hasNotifications<T>(store) ?
|
|
|
observe<Change<T>>(({ next }) => {
|
|
|
const handle = after(store, "notify", (...args: Change<T>) => next(args), true);
|
|
|
return () => handle.remove();
|
|
|
}).pipe(subject) : empty;
|
|
|
|
|
|
|
|
|
return (id: string | number, opts: GetOpts = {}) =>
|
|
|
observe<T>(({ next, complete, error }) => {
|
|
|
const result = store.get(id);
|
|
|
|
|
|
const handle = (x: T | null | undefined) => {
|
|
|
if (x !== null && x !== undefined)
|
|
|
next(x);
|
|
|
complete();
|
|
|
};
|
|
|
|
|
|
if (isPromise(result)) {
|
|
|
result.then(handle, error);
|
|
|
|
|
|
if (isCancellable(result))
|
|
|
return () => result.cancel();
|
|
|
} else {
|
|
|
handle(result);
|
|
|
}
|
|
|
}).cat(opts.observe !== false ? changes.pipe(filterItem(id)) : empty);
|
|
|
};
|
