Node.js for mobile developers

node.md

Node.js for mobile developers

Bryan Irace

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What is Node.js?

A platform built on Chrome's JavaScript runtime for easily building fast, scalable network applications. Node.js uses an event-driven, non-blocking I/O model that makes it lightweight and efficient, perfect for data-intensive real-time applications that run across distributed devices.

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Not a web framework or language

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Components

• V8 (Google's JavaScript engine)
• libuv (platform Independent I/O bindings)
• Core libraries (networking, modules, REPL, streams, logging)
• OpenSSL, etc.

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What's it good at?

• I/O
• Command line tools
• Not CPU-bound work

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Everything is asynchronous

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JavaScript

• Easy to learn
• Powerful
• Runs everywhere (you need to know it anyway...)
• Always getting faster
• Improving pretty rapidly
• Lots of good libraries

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NPM

##~70K modules

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package.json

{
  "name": "lunchr",
  "version": "1.0.0",
  "dependencies": {
    "express": "3.4.3",
    "request": "2.27.0",
    "underscore": "1.6.0"
  }
}

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Importing

var request = require('request');
var _       = require('underscore');
var qs      = require('querystring');
var express = require('express');

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Modules

• jQuery
• Underscore
• Express
• Async
• Request

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Express

var express = require('express');
var app = express();

app.get('/', function(req, res){
  res.send('Hello, world');
});

app.listen(3000);

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Async

async.parallel([
  function (callback) {
    ywa('1519698779', 'BOOKMARK_10135', callback);
  },
  function (callback) {
    play('com.tumblr', callback);
  }
], function (err, results) {
  if (err) {
    callback(err);
  }
  else {
    var ywa_data      = results[0]
      , play_rating   = results[1]

    // TODO
  }
}

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Request

request({
  url: 'https://rink.hockeyapp.net/api/2/apps/' + app_id + '/statistics',
  headers: {
    'X-HockeyAppToken': '61c40d6b6fac43d880e97c0bd22b4903'
  }
}, function (err, response, body) {
  if (err) {
    callback(err);
  }
  else {
    var versions = JSON.parse(body)['app_versions'];

    // TODO
  }
}

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jQuery

$('tr.stathead').remove();
$('tr').removeAttr('align').removeAttr('class');

$('tr:first').find('td').replaceWith(function () {
    return $('<th></th>')
        .html($(this).contents())
        .attr('data-week', index_of($(this)));
});

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Underscore

_.chain([1, 2, 3, 200])
  .filter(function(num) { 
    return num % 2 == 0; 
   })
  .map(function(num) { 
    return num * num 
   })
  .value();

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shell.js

require('shelljs/global');

if (!which('git')) {
  echo('Sorry, this script requires git');
  exit(1);
}

// Copy files to release dir
mkdir('-p', 'out/Release');
cp('-R', 'stuff/*', 'out/Release');

// Replace macros in each .js file
cd('lib');
ls('*.js').forEach(function(file) {
  sed('-i', 'BUILD_VERSION', 'v0.1.2', file);
  sed('-i', /.*REMOVE_THIS_LINE.*\n/, '', file);
  sed('-i', /.*REPLACE_LINE_WITH_MACRO.*\n/, cat('macro.js'), file);
});
cd('..');

// Run external tool synchronously
if (exec('git commit -am "Auto-commit"').code !== 0) {
  echo('Error: Git commit failed');
  exit(1);
}

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Hosting

• Easy to install
  • Windows
  • OS X (just a .dmg file)
• Easy to host
  • Heroku
  • Windows Azure

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Debugging

• node-inspector