0087e37f30
* Enable @typescript-eslint/consistent-type-imports lint rule This is to help ensure that we get proper vite/rollup lazy loading by not `import`ing more than we need to. Revert "Enable @typescript-eslint/consistent-type-imports lint rule" This reverts commit ba385fa00b7e410cc508fd5fb9fe972233ae114f. Enable @typescript-eslint/consistent-type-imports lint rule This is to help ensure that we get proper vite/rollup lazy loading by not `import`ing more than we need to. . * Format
41 lines
1.2 KiB
TypeScript
41 lines
1.2 KiB
TypeScript
/*
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Copyright 2023, 2024 New Vector Ltd.
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SPDX-License-Identifier: AGPL-3.0-only
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Please see LICENSE in the repository root for full details.
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*/
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import { type Observable, defer, finalize, scan, startWith, tap } from "rxjs";
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const nothing = Symbol("nothing");
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/**
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* RxJS operator that invokes a callback when the Observable is finalized,
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* passing the most recently emitted value. If no value was emitted, the
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* callback will not be invoked.
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*/
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export function finalizeValue<T>(callback: (finalValue: T) => void) {
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return (source: Observable<T>): Observable<T> =>
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defer(() => {
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let finalValue: T | typeof nothing = nothing;
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return source.pipe(
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tap((value) => (finalValue = value)),
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finalize(() => {
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if (finalValue !== nothing) callback(finalValue);
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}),
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);
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});
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}
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/**
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* RxJS operator that accumulates a state from a source of events. This is like
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* scan, except it emits an initial value immediately before any events arrive.
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*/
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export function accumulate<State, Event>(
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initial: State,
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update: (state: State, event: Event) => State,
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) {
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return (events: Observable<Event>): Observable<State> =>
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events.pipe(scan(update, initial), startWith(initial));
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}
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