From e4fa1e69e7ebfb627c7198fd1a9881e9327ec4d4 Mon Sep 17 00:00:00 2001 From: Pinapelz Date: Sat, 28 Jun 2025 17:26:46 -0700 Subject: initial commit: scaffolding --- node_modules/rxjs/src/internal/operators/last.ts | 91 ++++++++++++++++++++++++ 1 file changed, 91 insertions(+) create mode 100644 node_modules/rxjs/src/internal/operators/last.ts (limited to 'node_modules/rxjs/src/internal/operators/last.ts') diff --git a/node_modules/rxjs/src/internal/operators/last.ts b/node_modules/rxjs/src/internal/operators/last.ts new file mode 100644 index 0000000..698ce23 --- /dev/null +++ b/node_modules/rxjs/src/internal/operators/last.ts @@ -0,0 +1,91 @@ +import { Observable } from '../Observable'; +import { EmptyError } from '../util/EmptyError'; +import { OperatorFunction, TruthyTypesOf } from '../types'; +import { filter } from './filter'; +import { takeLast } from './takeLast'; +import { throwIfEmpty } from './throwIfEmpty'; +import { defaultIfEmpty } from './defaultIfEmpty'; +import { identity } from '../util/identity'; + +export function last(predicate: BooleanConstructor): OperatorFunction>; +export function last(predicate: BooleanConstructor, defaultValue: D): OperatorFunction | D>; +export function last(predicate?: null, defaultValue?: D): OperatorFunction; +export function last( + predicate: (value: T, index: number, source: Observable) => value is S, + defaultValue?: S +): OperatorFunction; +export function last( + predicate: (value: T, index: number, source: Observable) => boolean, + defaultValue?: D +): OperatorFunction; + +/** + * Returns an Observable that emits only the last item emitted by the source Observable. + * It optionally takes a predicate function as a parameter, in which case, rather than emitting + * the last item from the source Observable, the resulting Observable will emit the last item + * from the source Observable that satisfies the predicate. + * + * ![](last.png) + * + * It will emit an error notification if the source completes without notification or one that matches + * the predicate. It returns the last value or if a predicate is provided last value that matches the + * predicate. It returns the given default value if no notification is emitted or matches the predicate. + * + * ## Examples + * + * Last alphabet from the sequence + * + * ```ts + * import { from, last } from 'rxjs'; + * + * const source = from(['x', 'y', 'z']); + * const result = source.pipe(last()); + * + * result.subscribe(value => console.log(`Last alphabet: ${ value }`)); + * + * // Outputs + * // Last alphabet: z + * ``` + * + * Default value when the value in the predicate is not matched + * + * ```ts + * import { from, last } from 'rxjs'; + * + * const source = from(['x', 'y', 'z']); + * const result = source.pipe(last(char => char === 'a', 'not found')); + * + * result.subscribe(value => console.log(`'a' is ${ value }.`)); + * + * // Outputs + * // 'a' is not found. + * ``` + * + * @see {@link skip} + * @see {@link skipUntil} + * @see {@link skipLast} + * @see {@link skipWhile} + * @see {@link first} + * + * @throws {EmptyError} Delivers an `EmptyError` to the Observer's `error` + * callback if the Observable completes before any `next` notification was sent. + * + * @param predicate The condition any source emitted item has to satisfy. + * @param defaultValue An optional default value to provide if last `predicate` + * isn't met or no values were emitted. + * @return A function that returns an Observable that emits only the last item + * satisfying the given condition from the source, or an error notification + * with an `EmptyError` object if no such items are emitted. + */ +export function last( + predicate?: ((value: T, index: number, source: Observable) => boolean) | null, + defaultValue?: D +): OperatorFunction { + const hasDefaultValue = arguments.length >= 2; + return (source: Observable) => + source.pipe( + predicate ? filter((v, i) => predicate(v, i, source)) : identity, + takeLast(1), + hasDefaultValue ? defaultIfEmpty(defaultValue!) : throwIfEmpty(() => new EmptyError()) + ); +} -- cgit v1.2.3