javascript_practice/hw13/stage5.js

function jsonPost(url, data) {
	return new Promise((resolve, reject) => {
		const x = new XMLHttpRequest();
		x.onerror = () => reject(new Error('jsonPost failed'))
		//x.setRequestHeader('Content-Type', 'application/json');
		x.open("POST", url, true);
		x.send(JSON.stringify(data))

		x.onreadystatechange = () => {
			if (x.readyState === XMLHttpRequest.DONE && x.status === 200){
				resolve(JSON.parse(x.responseText))
			} else if (x.status !== 200){
				reject(new Error('status is not 200'))
			}
		}
	});
}

//Stage 0 && Stage 1
const url = "http://students.a-level.com.ua:10012";
let nextId = 0;

const delay = ms => new Promise(ok => setTimeout(() => ok(ms), ms));

const addZero = data => data < 10 ? `0${data}` : data;

const buildDate = date => `${date.getDate()}/${date.getMonth()+1}/${date.getFullYear()} ${addZero(date.getHours())}:${addZero(date.getMinutes())}:${addZero(date.getSeconds())}`;

const buildMessage = (nick, message, time) => {
	return `<p>nick - ${nick}, message - ${message}, date - ${buildDate(new Date(time))}</p>`;
}

const sendMessage = async (nick, message) => {
	await jsonPost(url, {func: 'addMessage', nick: nick, message: message});
}

const getMessages = async () => {
	let messagesArray = await jsonPost(url, {func: 'getMessages', messageId: nextId});
	for (const message of messagesArray.data) {
		chatMessages.insertAdjacentHTML('afterbegin', buildMessage(message.nick, message.message, message.timestamp));
	}
	nextId = messagesArray.nextMessageId;
}

const sendAndCheck = async (nick, message) => {
	await Promise.all([sendMessage(nick, message), getMessages()]);
}

const checkLoop = async () => {
	while (true) {
		await Promise.all([delay(5000), getMessages()]);
	}
}

sendButton.addEventListener('click', () => {
	let nickValue = nickInput.value;
	let messageValue = messageInput.value;
	sendAndCheck(nickValue, messageValue);
});

checkLoop();