--- /dev/null
+import { MonoTypeOperatorFunction } from '../types';
+/**
+ * If the source observable completes without emitting a value, it will emit
+ * an error. The error will be created at that time by the optional
+ * `errorFactory` argument, otherwise, the error will be {@link EmptyError}.
+ *
+ * ![](throwIfEmpty.png)
+ *
+ * ## Example
+ * ```ts
+ * import { fromEvent, timer } from 'rxjs';
+ * import { throwIfEmpty, takeUntil } from 'rxjs/operators';
+ *
+ * const click$ = fromEvent(document, 'click');
+ *
+ * click$.pipe(
+ * takeUntil(timer(1000)),
+ * throwIfEmpty(
+ * () => new Error('the document was not clicked within 1 second')
+ * ),
+ * )
+ * .subscribe({
+ * next() { console.log('The button was clicked'); },
+ * error(err) { console.error(err); }
+ * });
+ * ```
+ *
+ * @param errorFactory A factory function called to produce the
+ * error to be thrown when the source observable completes without emitting a
+ * value.
+ */
+export declare function throwIfEmpty<T>(errorFactory?: (() => any)): MonoTypeOperatorFunction<T>;