RocketChat/Rocket.Chat

import type { IUser } from '@rocket.chat/core-typings';
/*
    In contrary to getUserDisplayName, this function returns an array of strings, containing name & username in the order they're supposed to be displayed.
*/
export const getUserDisplayNames = (
    name: IUser['name'],
    username: IUser['username'],
    useRealName: boolean,
): [nameOrUsername: string, username?: string] => {
    if (!username) {
        throw new Error('Username is required');
    }
    const shouldUseName = !!(useRealName && name);

    return shouldUseName ? [name, username] : [username];
};