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Diffstat (limited to 'node_modules/rxjs/src/internal/firstValueFrom.ts')
| -rw-r--r-- | node_modules/rxjs/src/internal/firstValueFrom.ts | 75 |
1 files changed, 0 insertions, 75 deletions
diff --git a/node_modules/rxjs/src/internal/firstValueFrom.ts b/node_modules/rxjs/src/internal/firstValueFrom.ts deleted file mode 100644 index 2fc4bcf..0000000 --- a/node_modules/rxjs/src/internal/firstValueFrom.ts +++ /dev/null @@ -1,75 +0,0 @@ -import { Observable } from './Observable'; -import { EmptyError } from './util/EmptyError'; -import { SafeSubscriber } from './Subscriber'; - -export interface FirstValueFromConfig<T> { - defaultValue: T; -} - -export function firstValueFrom<T, D>(source: Observable<T>, config: FirstValueFromConfig<D>): Promise<T | D>; -export function firstValueFrom<T>(source: Observable<T>): Promise<T>; - -/** - * Converts an observable to a promise by subscribing to the observable, - * and returning a promise that will resolve as soon as the first value - * arrives from the observable. The subscription will then be closed. - * - * If the observable stream completes before any values were emitted, the - * returned promise will reject with {@link EmptyError} or will resolve - * with the default value if a default was specified. - * - * If the observable stream emits an error, the returned promise will reject - * with that error. - * - * **WARNING**: Only use this with observables you *know* will emit at least one value, - * *OR* complete. If the source observable does not emit one value or complete, you will - * end up with a promise that is hung up, and potentially all of the state of an - * async function hanging out in memory. To avoid this situation, look into adding - * something like {@link timeout}, {@link take}, {@link takeWhile}, or {@link takeUntil} - * amongst others. - * - * ## Example - * - * Wait for the first value from a stream and emit it from a promise in - * an async function - * - * ```ts - * import { interval, firstValueFrom } from 'rxjs'; - * - * async function execute() { - * const source$ = interval(2000); - * const firstNumber = await firstValueFrom(source$); - * console.log(`The first number is ${ firstNumber }`); - * } - * - * execute(); - * - * // Expected output: - * // 'The first number is 0' - * ``` - * - * @see {@link lastValueFrom} - * - * @param source the observable to convert to a promise - * @param config a configuration object to define the `defaultValue` to use if the source completes without emitting a value - */ -export function firstValueFrom<T, D>(source: Observable<T>, config?: FirstValueFromConfig<D>): Promise<T | D> { - const hasConfig = typeof config === 'object'; - return new Promise<T | D>((resolve, reject) => { - const subscriber = new SafeSubscriber<T>({ - next: (value) => { - resolve(value); - subscriber.unsubscribe(); - }, - error: reject, - complete: () => { - if (hasConfig) { - resolve(config!.defaultValue); - } else { - reject(new EmptyError()); - } - }, - }); - source.subscribe(subscriber); - }); -} |
