Rocket.Chat/packages/rocketchat-api/server/v1/emoji-custom.js

import { Meteor } from 'meteor/meteor';
RocketChat.API.v1.addRoute('emoji-custom', { authRequired: true }, {
	get() {
		const emojis = Meteor.call('listEmojiCustom');

		return RocketChat.API.v1.success({ emojis });
	},
});