feat: initial commit

node_modules/rxjs/internal/operators/single.d.ts

@@ -0,0 +1,49 @@
+import { Observable } from '../Observable';
+import { MonoTypeOperatorFunction } from '../types';
+/**
+ * Returns an Observable that emits the single item emitted by the source Observable that matches a specified
+ * predicate, if that Observable emits one such item. If the source Observable emits more than one such item or no
+ * items, notify of an IllegalArgumentException or NoSuchElementException respectively. If the source Observable
+ * emits items but none match the specified predicate then `undefined` is emitted.
+ *
+ * <span class="informal">Like {@link first}, but emit with error notification if there is more than one value.</span>
+ * ![](single.png)
+ *
+ * ## Example
+ * emits 'error'
+ * ```ts
+ * import { range } from 'rxjs';
+ * import { single } from 'rxjs/operators';
+ *
+ * const numbers = range(1,5).pipe(single());
+ * numbers.subscribe(x => console.log('never get called'), e => console.log('error'));
+ * // result
+ * // 'error'
+ * ```
+ *
+ * emits 'undefined'
+ * ```ts
+ * import { range } from 'rxjs';
+ * import { single } from 'rxjs/operators';
+ *
+ * const numbers = range(1,5).pipe(single(x => x === 10));
+ * numbers.subscribe(x => console.log(x));
+ * // result
+ * // 'undefined'
+ * ```
+ *
+ * @see {@link first}
+ * @see {@link find}
+ * @see {@link findIndex}
+ * @see {@link elementAt}
+ *
+ * @throws {EmptyError} Delivers an EmptyError to the Observer's `error`
+ * callback if the Observable completes before any `next` notification was sent.
+ * @param {Function} predicate - A predicate function to evaluate items emitted by the source Observable.
+ * @return {Observable<T>} An Observable that emits the single item emitted by the source Observable that matches
+ * the predicate or `undefined` when no items match.
+ *
+ * @method single
+ * @owner Observable
+ */
+export declare function single<T>(predicate?: (value: T, index: number, source: Observable<T>) => boolean): MonoTypeOperatorFunction<T>;