Kovalsky

function delay(timeout) {
	return new Promise(res => setTimeout(res, timeout));
}

async function sendMessage(user, message) {
	/* example */
	console.log(user, message);
	/* example */
}

async function sendAllTheMessagesToOurLovelyUsers(mailing_data, delay_between_requests) {
	for (let mailing_entry of Object.values(mailing_data)) {
		for (let user of mailing_entry.users) {
			await sendMessage(user, mailing_entry.msg);
			await delay(delay_between_requests);			
		}
	}
};

sendAllTheMessagesToOurLovelyUsers([
	{
		users: [
			{ user_id: 25 },
			{ user_id: 14 },
		],
		msg: "message1"
	}, 
	{
		users: [
			{ user_id: 14 },
			{ user_id: 6 }
		],
		msg: "message2"
	}
], 500);

function delay(timeout) {
	return new Promise(res => setTimeout(res, timeout));
}

async function sendMessage(user) {
	/* example */
	console.log(user);
	/* example */
}

async function sendAllTheMessagesToOurLovelyUsers(user_lists, delay_between_requests) {
	const users = {};

	for (let user of user_lists.flat()) {
		/* пример процедуры получения массива уникальных пользователей */
		if (!(users[ user.user_id ] in users)) {
			users[ user.user_id ] = user;
		}
	}

	for (let user of Object.values(users)) {
		await sendMessage(user);
		await delay(delay_between_requests);
	}	
};

sendAllTheMessagesToOurLovelyUsers([
	[
		{ user_id: 25 },
		{ user_id: 14 },
	],
	[
		{ user_id: 14 },
		{ user_id: 6 }
	]
], 500);

(() => {
  const re_template = /{(.*?)}/g;

  String.prototype.process = function(data) {
    return this.replace(re_template, (entry, word) => data[ word ]);
  }
})();

let templates = {
  greeting: 'Hello, my name is {name} and my age is {age}'
};

// Напрямую:
templates.greeting.process({ name: 'Yeshua', age: 2019 });
// Hello, my name is Yeshua and my age is 2019
templates.threat.process({ reason: 'i dont like you' });
// TypeError: Cannot read property 'process' of undefined


// Или автоматически вызывая process с помощью Proxy:
// (то же можно было реализовать просто с помощью дополнительной функции)
templates = new Proxy(templates, {
    get(target, prop) {
    	if (prop in target) {
        	return String.prototype.process.bind(target[prop]);
        } else {
        	throw new Error(`String "${ prop }" was not found in storage!`);
        }
    }
});

templates.greeting({ name: 'Yeshua', age: 2019 });
// Hello, my name is Yeshua and my age is 2019
templates.threat({ reason: 'i dont like you' });
// Error: String "threat" was not found in storage!

const types = [];
types[2] = 'OPEN_MODAL';
types[3] = 'CLOSE_MODAL';