The State of RVA.JavaScript

James Long

RVA.js, Oct 2013

Who am I?

• James Long
• Mozilla, Apps Engineering
• JavaScript Expert
• nunjucks (templating engine)
• outlet (Lisp dialect)
• shade (3d WebGL engine)

About RVA.js

Taking a pulse of Richmond's tech scene

• Can Richmond's tech scene do better?
• How can we help?
• Do people want to learn about JavaScript?

What is this thing, JavaScript?

JavaScript is the language of the web, and more.

JavaScript != jQuery

Just like Ruby is not Rails and Python is not Django,

JavaScript is not jQuery.

In fact, it's so much more than that.

History

• Originally developed by Brendan Eich in 10 days
  
• In 1995, first shipped in Netscape Navigator as LiveScript.
• Renamed to JavaScript shortly thereafter, gained wild popularity and success. Rest is history.
  

History

In 1996, JavaScript given to ECMA for standardization under the name ECMAScript

Trivia time. ECMA also standardizes:

• 8-inch floppy disk (also 5.25" and 3.5")
  
• CD-ROM volume and filestructure
• C# language specification

Today

Powers millions of websites

4 extremely advanced and competitive implementations (JIT-able engines)

Diverse, rich culture

Today

Haters gonna hate

(we could have been stuck with VBScript)

The language is good, but it takes some learning

The real power: platform and community

Powerful Webapps

Rich client/server architectures

Revolutionary frameworks like backbone, ember, angular

Simple, Efficient Backends

Games

WebGL

Games

So Let's Talk JavaScript

function foo(x, y) {
  return x + y;
}

console.log(4, 6); // -> 10

So Let's Talk JavaScript

function foo() {
  var sum = 0;

  for(var i=0; i<arguments.length; i++) {
    sum += arguments[i];
  }

  return sum;
}

console.log(4, 6, 5); // -> 15

So Let's Talk JavaScript

function foo() {
  _.reduce(arguments, function(total, num) {
    return total + sum;
  }, 0);
}

console.log(4, 6, 5); // -> 15

Functional Programming

Functions are first-class values

function foo() {}

var foo = function() {}

bar(1, 2, 3, function() {});

Functional Programming

This single feature allowed JavaScript to thrive despite its shortcomings

• async (callbacks)
• modules
• private data
• many other interesting programming models
• fully dynamic, ready for the recent explosion of
  dynamic languages
  

Closures

function foo(x) {
  return function(y) {
    return x + y;
  }
}

var sum10 = foo(10);

console.log(sum10(5)); // -> 15

Closures

function getStatus(obj) {
  var fullname = obj.first + ' ' + obj.last;

  return function() {
    $.get('/status', { name: fullname }, function(res) {
      $('.result').text(res);
    }
  }
}

var req = getStatus({ first: 'James', last: 'Long' });

// later...

req();

ES6

• variable destructuring

  var [x, y] = [5, 6];
  var {x ,y} = {x: 5, y: 6};

• generators (like Python's `yield`)        
  
• arrow function syntax
  

  [0, 1, 2].map(function(x) { return x + 1; });
  
  [0, 1, 2].map(x => x + 1);

• block scoping: `let`
• proxies, maps, sets, modules
  

Developing JavaScript

Not Convinced?

Firefox OS

So Back to RVA

What do you want out of this group?

Tell us what you work on, and

what you're interested in!

Thanks

http://jlongster.com/