MentionFeed

// Static configuration.
const mentionFeedPeople = {
	marker: '@',
	feed: [ '@Alice', '@Bob', ... ],
	minimumCharacters: 2
};

// Simple synchronous callback.
const mentionFeedTags = {
	marker: '#',
	feed: ( searchString: string ) => {
		return tags
			// Filter the tags list.
			.filter( tag => {
				return tag.toLowerCase().includes( queryText.toLowerCase() );
			} )
	}
};

const tags = [ 'wysiwyg', 'rte', 'rich-text-edior', 'collaboration', 'real-time', ... ];

// Asynchronous callback.
const mentionFeedPlaceholders = {
	marker: '$',
	feed: ( searchString: string ) => {
		return getMatchingPlaceholders( searchString );
	}
};

function getMatchingPlaceholders( searchString: string ) {
	return new Promise<Array<MentionFeedItem>>( resolve => {
		doSomeXHRQuery( result => {
			// console.log( result );
			// -> [ '$name', '$surname', '$postal', ... ]

			resolve( result );
		} );
	} );
}