Better.js
For A Better Javascript In Javascript
A Better Javascript In Javascript ?
Like... javascript is not perfect ??
Javascript WTF
The Horrors
negative zero equal but not equal
0 === -0 //true
1/0 === 1/-0 //false
source
Parseint Magic
parseInt(null, 24) === 23 // true
source
Identity Crisis
var foo = [0];
console.log(foo == !foo); // => true
console.log(foo == foo); // => true
Heard the rumor of maybe operator in ES6 ?
source
Concat Coerce
"3" + 1 // '31'
"3" - 1 // 2
source
OK... so javascript is far from perfect.
How to deal with Javascript Issues
- People are trying to fix them. Good
- What are they ? People dont agree
- How to fix them ? They really disagree
Alternatives
Just to name a few...
Different Syntaxes
- new languages to learn
- require time for your team to train
- less docs and examples on the web
Require compilation
- more complex build
- slower developement iterations
- harder to debug
Vendor Tainted
- microsoft, google, mozilla, facebook...
- estimated time to converge... infinity+1 :)
They All Attack Javascript
But me...
I Love Javascript!
I am the Javascript Knight
I am defending Javascript Against Evil Attackers
Javascript is The King
- Javascript is open standard
- Javascript run everywhere
- You can't beat that.
Meanwhile we, the webdevs, are stuck with javascript...
Plain Old Javascript
Engaged Super Power
How to improve Javascript In Javascript ?
What Is Better.js
- 100% Plain Old Javascript
- unintrusive javascript library
- focused on helping you write better javascript
"Make writting JS safer, faster and easier"
Braging Time
Better.js Provides Features Unseen to Javascript
Javascript got no Private!
Think Again!
with Better.js it does!
Javascript got no Strong Typing!
Think Again!
with Better.js it does!
Better.js is funky!
It is "Not your mother Javascript!"
- Provides Strong Typing to Javascript
- Provides Private Visibility to Javascript
Features unseen in Javascript World!
100% Plain Old Javascript
- No compilation Step
- No New Language to Learn
Better.js is 100% Plain Old Javascript
First...
Strong Typing in Javascript
An example
Sample Function
var cat = function(name, age){
console.log('my name is', name, 'and im', age)
}
- Simple function to display a message
- receive a String
name
- receive a Number
age
Play with Strong Typing In JS
- Define a function class
- Make a Better.js declaration for its arguments
- works for function return types too
- works for object property too
- See what happen
Make a Better.js for it
cat = BetterJS.Function(cat, {
arguments : [String, Number],
})
- You overload
Cat function
- Define the types for each arguments
- Better.js makes sure it is respected!
Let's See What Happens
Calling the function with valid types - OK
cat('kitty', 5)
// display 'My name is kitty and im 5.'
Let's See What Happens
Calling the function with invalid types - BAD
cat('kitty', 'ten')
// Exception thrown
// "Invalid arguments 1 - Should be Number"
Error Immediatly detected and execution stopped
Strong Typing in Better.js
- Better.js provides strong typing to JS! COOL!
- Unauthorized access is immediatly detected
Earlier bug detection, so helps you write better js
Second ...
Private in Javascript
An example
Sample Class
var Cat = function(name){
this._name = name
this.age = 7
}
Cat.prototype.getName = function(){
return this._name
}
- Let's define a nice kitty class.
._name is a private property .getName() is its getter
Play with Private In Better.js
- Define a sample class
- Make a Better.js declaration for it
- See what happen
Make a Better.js for it
Cat = BetterJS.Class(Cat, {
privatize : true
})
- You overload
Cat constructor
- Now
._name is private
- After that, you can access it only if you are the class
Let's See What Happens
Create an instance for your class
var cat = new Cat('kitty')
Let's See What Happens (bis)
Accessing public property .age - OK
console.log('cat age is ', cat.age)
// Display "cat age is 7"
Let's See What Happens (bis)
Now calling the getter .getName() - OK
console.log('cat name is ', cat.getName())
Let's See What Happens (bis)
Now accessing the private property ._name - BAD
console.log('cat name is ', cat._name)
Error Immediatly detected and execution stopped
Private in Better.js
- Better.js provides private visibility to JS! *COOL!
- Unauthorized access are immediatly detected
Earlier bug detection, so helps you write better js
What better.js brings to the table ?
- better.js brings private visibility to JS
- better.js brings strong typing to JS
Not Bad!
What better.js changes ?
- 2 Major features
- Both unseen in JS
Result
- Helps you write Safer Javascript
- Helps you find bug Earlier
Better.js Spirit
"Make writting JS safer, faster and easier"
- 100% plain javascript
- earlier bug detections
- monitor excutions
What Better.js will be Doing
- object allocation tracking
- garbage collector monitoring
- function caller tracking
- global variable detector
Features not yet exposed, but coded
