import { Subject } from 'rxjs';
/**
 *  `source` returns an object that extends an RxJS [Subject](https://rxjs.dev/guide/subject) with an extra `type: string` property, and is also callable directly.
 *  When using a `source`, you can provide a `type` argument, which will appear as the action type in Redux DevTools:
 *
 *  ![Action Type in Redux Devtools](https://state-adapt.github.io/assets/devtools-add$.png)
 *
 *  In the future we want to add a build step to add this annotation automatically. That is why source types are optional.
 *
 *  #### Example: Creating a source without a type
 *
 *  ```typescript
 *  import { source } from '@state-adapt/rxjs';
 *
 *  const add$ = source<number>();
 *
 *  add$.subscribe(console.log);
 *
 *  add$.next(1);
 *  // 1
 *
 *  add$(2)
 *  // 2
 *  ```
 *
 *  #### Example: Creating a source with a type
 *  ```typescript
 *  const add$ = source<number>('add$');
 *  ```
 *
 *  #### Example: Creating a source with onEvent naming convention
 *  ```typescript
 *  import { source } from '@state-adapt/rxjs';
 *
 *  const onAdd = source<number>();
 *
 *  onAdd.subscribe(console.log);
 *
 *  onAdd(1)
 *  // 1
 *  ```
 */
export declare function source<T>(type?: string): SourceFn<T>;
export type SourceFn<T> = (unknown extends T ? () => void : (payload: T) => void) & Subject<T>;