Generating a startup script
# Detect available init system, generate configuration and enable startup system pm2 startup
Generating a startup script
pm2 save
Disabling startup system
pm2 unstartup
References
http://pm2.keymetrics.io/docs/usage/startup/
curl -sS https://dl.yarnpkg.com/debian/pubkey.gpg | sudo apt-key add - echo "deb https://dl.yarnpkg.com/debian/ stable main" | sudo tee /etc/apt/sources.list.d/yarn.list
sudo apt-get update && sudo apt-get install yarn
References
https://yarnpkg.com/lang/en/docs/install/#debian-stable
function getSchool(name: string, address?: string, pinCode?: string): string {
if (address == undefined) {
console.log('address not defined');
}
if (pinCode == undefined) {
console.log('pincode not defined');
}
//...
}
References
http://dotnetpattern.com/typescript-optional-parameters
// sending to individual socketid (private message)
io.to(`${socketId}`).emit('hey', 'I just met you');
// WARNING: `socket.to(socket.id).emit()` will NOT work, as it will send to everyone in the room
// named `socket.id` but the sender. Please use the classic `socket.emit()` instead.
References
https://socket.io/docs/emit-cheatsheet/
socket.on('connect', () => {
// ...
});
// note: you should register event handlers outside of connect,
// so they are not registered again on reconnection
socket.on('myevent', () => {
// ...
});
References
https://socket.io/docs/client-api/#Event-%E2%80%98connect%E2%80%99
As with broadcasting, the default is all clients from the default namespace (‘/’):
const io = require('socket.io')();
io.clients((error, clients) => {
if (error) throw error;
console.log(clients); // => [6em3d4TJP8Et9EMNAAAA, G5p55dHhGgUnLUctAAAB]
});
Gets a list of client IDs connected to specific namespace (across all nodes if applicable):
const io = require('socket.io')();
io.of('/chat').clients((error, clients) => {
if (error) throw error;
console.log(clients); // => [PZDoMHjiu8PYfRiKAAAF, Anw2LatarvGVVXEIAAAD]
});
An example to get all clients in namespace’s room:
const io = require('socket.io')();
io.of('/chat').in('general').clients((error, clients) => {
if (error) throw error;
console.log(clients); // => [Anw2LatarvGVVXEIAAAD]
});
Server
var io = require('socket.io')(80);
io.on('connection', function (socket) {
socket.broadcast.emit('user connected');
});
var io = require('socket.io')(80);
io.on('connection', function (socket) {
var tweets = setInterval(function () {
getBieberTweet(function (tweet) {
socket.volatile.emit('bieber tweet', tweet);
});
}, 100);
socket.on('disconnect', function () {
clearInterval(tweets);
});
});
Server
var io = require('socket.io')(80);
var chat = io
.of('/chat')
.on('connection', function (socket) {
socket.emit('a message', {
that: 'only'
, '/chat': 'will get'
});
chat.emit('a message', {
everyone: 'in'
, '/chat': 'will get'
});
});
var news = io
.of('/news')
.on('connection', function (socket) {
socket.emit('item', { news: 'item' });
});
Client
<script>
var chat = io.connect('http://localhost/chat')
, news = io.connect('http://localhost/news');
chat.on('connect', function () {
chat.emit('hi!');
});
news.on('news', function () {
news.emit('woot');
});
</script>
References
https://socket.io/docs/#Restricting-yourself-to-a-namespace
Socket.IO allows you to emit and receive custom events. Besides
connect,messageanddisconnect, you can emit custom events
Server
io.on('connection', function (socket) {
socket.on("msg1", function (from, msg) {
console.log('I received a message by ', from, ' saying ', msg);
});
});
Client
$(document).ready(function () {
var socket = io.connect('http://localhost:14000');
socket.emit("msg1", "Mahmood", "Hello");
});
References
https://socket.io/docs/#Sending-and-receiving-events