17 lines
636 B
TypeScript
17 lines
636 B
TypeScript
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import * as plugins from './smartstate.plugins.js';
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import { combineLatest, map } from 'rxjs';
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import type { StatePart } from './smartstate.classes.statepart.js';
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/**
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* creates a computed observable derived from multiple state parts.
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* the observable is lazy — it only subscribes to sources when subscribed to.
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*/
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export function computed<TResult>(
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sources: StatePart<any, any>[],
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computeFn: (...states: any[]) => TResult,
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): plugins.smartrx.rxjs.Observable<TResult> {
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return combineLatest(sources.map((sp) => sp.select())).pipe(
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map((states) => computeFn(...states)),
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) as plugins.smartrx.rxjs.Observable<TResult>;
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}
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