Ngaji NodeJs

Ngaji NodeJs
GLiB
http://glibogor.or.id
Minggu, 8 November 2015

Javascript
● ECMA Script
● Bahasa skrip, ada intreperter
● Dynamic Type

NodeJS
● Bukan bahasa, bukan framework.
● Jalan di atas mesin V8 dari Google
● Terdiri dari :
– Runtime environment
– API / pustaka bawaan (beberapa berbeda
dengan API / pustaka bawaan di peramban)
●

Mengapa?
● Sementara ini paling populer di statistik GitHub
● Perkakas pengembangan front-end banyak
yang bergantung ke modul NPM
● Bahasa yang sama depan belakang
● Non-blocking IO
● Asyik buat aplikasi berbasis jaringan (http,
websocket)

Mengapa jangan?
● Basis data relasional
● Komputasi berat

Pasang
● Paket manajer dari sistem operasi (apt, yum,
brew)
● NVM (Node Version Manager)
● Kompilasi sendiri

Fungsi
var cetak = function(string){
console.log(string);
}
cetak(“hai”);

Fungsi
var foo = false;
var assignTrue = function(){
return true;
}
foo = assignTrue();
console.log(foo);

Fungsi
function cetak(string1, string2) {
console.log(string1 + “ “ + string2);
}
cetak(“hai”, “kamu”);
cetak(1, “orang”);

Callback
var cetak = function(string, cb){
console.log(string);
if (cb) {
cb();
}
}
cetak(“assalamualaikumn”, function(){
console.log(“waalaikumsalamn”);
});
cetak(“hain”);

Callback
cetak(“assalamualaikumn”, function(){
cetak(“waalaikumsalamn”, function(){
console.log(“kapan?n”);
});
});

Callback
var splitName = function(fullName, callback){
var firstName = fullName.split(“ “)[0];
var lastName = fullname.split(“ “)[1];
callback(firstName, lastName);
}
splitName(“peregrin took”, function(first, last){
console.log(first + “ “ + last);
})

Common Callback Pattern
var isOdd = function(int, cb){
var err;
var result;
if (typeof int != “number”) {
err = new Error(“Not a number!”);
return cb(err);
}
if (int % 2 == 0) {
cb(null, true);
} else (int % 2 == 1) {
cb(null, false);
}
}
isOdd(function(err, result){
if (err) {
return console.log(result);
}
console.log(result);
})

Callback Hell
cetak1(input, function(result){
cetak2(result, function(result){
});
});
});
});
});

cetak(input)
return fungsi1(result);
})
})
})
})
})
})
.catch(function(err){
// Handle error
});

Sync
console.log(1);
console.log(2);
console.log(3);
console.log(4);
var a = foo1();
var b = foo2(a);
var c = foo3(b);
var d = foo4(c);

Async
console.log(1);
getNumber(function(number){
console.log(number); // number = 2
// do some thing ...
});
console.log(3);
console.log(4);

Async
var data = “hai kamu ~”;
sendSMS(data, function(err, result){
// save sent sms to sent box,
// notify sender
// do some thing...
});
saveToDB(data, function(err, result){
// emit a socket communication
// do some thing other
});

Command Argument
console.log(process.argv[1]);
-------------------------------------
$ node cetak.js “halo”

Environment Variable
console.log(“Running on :”);
console.log(process.env.HOST + “:” process.env.PORT);
-------------------------------------
$ HOST=10.0.0.1 PORT=3001 node index.js

fs API
Sync
----------------------------------------------
var fs = require(“fs”);
var ls = fs.readdirSync(“./”);
Async
----------------------------------------------
var fs = require(“fs”);
var ls;
fs.readdir(function(err, result){
if (err) {
// Handle error
}
ls = result;
})

Require
cetak.js
–------------------------------------------
var cetak = function(){
console.log(“yooo!”);
}
module.exports = cetak;
index.js
-------------------------------------------
var cetak = require(“cetak”);
cetak();

Require
cetak.js
–------------------------------------------
var hai = function(){
console.log(“hai”);
}
var halo = function(){
console.log(“halo”);
}
exports.hai = hai;
exports.halo = halo;
index.js
-------------------------------------------
var cetak = require(“cetak”);
cetak.hai();

cetak.js
–------------------------------------------
var Cetak = function(){}
Cetak.prototype.halo = function(){
console.log(“halo”);
}
Cetak.prototype.hai = function(){
console.log(“hai”);
}
module.exports = Cetak;
index.js
-------------------------------------------
var Cetak = require(“cetak”);
var cetak = new Cetak();
cetak.halo();

NPM
● npmjs.org
$ npm install wooosaaah

NPM
index.js
-------------------------------------------
var md5 = require(“md5”);
md5(“hai”);

NPM
● npm init
● npm install --save namapaket
● npm install –save-dev namapaket

Bangun
● Webserver sederhana

Webserver
index.js
-------------------------------------------
var express = require("express"),
app = express();
app.get("/", function(req, res) {
res.send("website webdong");
});
app.listen(3000, "localhost", function(){
console.log("Webnya udah jalandong");
});

Ngaji NodeJs

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