wp-calypso/client/reader/components/reader-main/pending-action-handler.tsx

import { useEffect } from 'react';
import { useDispatch, useSelector } from 'calypso/state';
import { likeComment } from 'calypso/state/comments/actions';
import { isUserLoggedIn } from 'calypso/state/current-user/selectors';
import { like } from 'calypso/state/posts/likes/actions';
import { follow } from 'calypso/state/reader/follows/actions';
import { requestFollowTag } from 'calypso/state/reader/tags/items/actions';
import { clearLastActionRequiresLogin } from 'calypso/state/reader-ui/actions';
import { getPersistedLastActionPriorToLogin } from 'calypso/state/reader-ui/selectors';

export const ReaderPendingActionHandler = () => {
	const dispatch = useDispatch();
	const isLoggedIn = useSelector( isUserLoggedIn );
	const pendingAction = useSelector( getPersistedLastActionPriorToLogin );

	useEffect( () => {
		if ( ! isLoggedIn || ! pendingAction ) {
			return;
		}

		// The timeout is a naieve attempt to try and combat race conditions. Initial requests from
		// the app loading could come back slower than what is dispatched here, causing a stale
		// state in the UI. However, there doesn't seem to be a good indicator for when all of these
		// potential items may already be loaded or some circumstances where they wouldn't be which
		// makes it difficult to evaluate this timing differently.
		setTimeout( () => {
			switch ( pendingAction.type ) {
				case 'like':
					dispatch( like( pendingAction.siteId, pendingAction.postId ) );
					break;
				case 'comment-like':
					dispatch(
						likeComment( pendingAction.siteId, pendingAction.postId, pendingAction.commentId )
					);
					break;
				case 'follow-site':
					dispatch( follow( pendingAction.siteUrl, pendingAction.followData, null ) );
					break;
				case 'follow-tag':
					dispatch( requestFollowTag( pendingAction.tag ) );
					break;
			}
		}, 2000 );

		dispatch( clearLastActionRequiresLogin() );
	}, [ isLoggedIn, pendingAction, dispatch ] );

	return null;
};