Rocket.Chat.ReactNative/app/containers/MessageBox/constants.ts

export const MENTIONS_TRACKING_TYPE_USERS = '@';
export const MENTIONS_TRACKING_TYPE_EMOJIS = ':';
export const MENTIONS_TRACKING_TYPE_COMMANDS = '/';
export const MENTIONS_TRACKING_TYPE_ROOMS = '#';
export const MENTIONS_TRACKING_TYPE_CANNED = '!';
export const MENTIONS_COUNT_TO_DISPLAY = 4;
export const MAX_EMOJIS_TO_DISPLAY = 20;

export const TIMEOUT_CLOSE_EMOJI = 300;