cocktail
v0.7.3
Published
CocktailJS is a small library to explore traits, talents, inheritance and annotations concepts in nodejs - Shake your objects and classes with Cocktail!
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Cocktail JS
Cocktail is a small but yet powerful library with very simple principles:
- Reuse code
- Keep it simple
Reuse code
Cocktail explores three mechanisms to share/reuse/mix code:
- Extends: OOP inheritance implemented in Javascript.
- Traits: Traits are composable behavior units that can be added to a Class.
- Talents: Same idea as Traits but applied to instances of a Class.
Keep it simple
Cocktail has only one public method cocktail.mix()
but it relies on annotations
to tag some meta-data that describe the mix.
Annotations
Annotations are simple meta-data Cocktail uses to perform some tasks over the given mix. They become part of the process but usually they are not kept in the result of a mix.
var cocktail = require('cocktail'),
MyClass = function(){};
cocktail.mix(MyClass, {
'@properties': {
name: 'default name'
}
});
In the example above we created a "Class" named MyClass, and we use the @properties
annotation to create the property name and the corresponding setName and getName methods.
As it was mentioned before, annotations are meta-data, which means that they are not part of MyClass or its prototype.
Defining a Class / Module
Using cocktail to define a class is easy and elegant.
var cocktail = require('cocktail');
cocktail.mix({
'@exports': module,
'@as': 'class',
'@properties': {
name: 'default name'
},
constructor: function(name){
this.setName(name);
},
sayHello: function() {
return 'Hello, my name is ' + this.getName();
}
});
In this example our class definition uses @exports
to tell the mix we want to export the result in the module.exports
and @as
tells it is a class.
Traits
Traits are Composable Units of Behaviour (You can read more from this paper). Basically, a Trait is a Class, but a special type of Class that has only behaviour (methods) and no state. Traits are an alternative to reuse behaviour in a more predictable manner. They are more robust than Mixins, or Multiple Inheritance since name collisions must be solved by the developer beforehand. If you compose your class with one or more Traits and you have a method defined in more than one place, your program will fail giving no magic rule or any kind of precedence definition.
Enumerable.js
var cocktail = require('cocktail');
cocktail.mix({
'@exports': module,
'@as': 'class',
'@requires': ['getItems'],
first: function() {
var items = this.getItems();
return items[0] || null;
},
last: function() {
var items = this.getItems(),
l = items.length;
return items[l-1];
}
});
The class above is a Trait declaration for an Enumerable functionality.
In this case we only defined first
and last
methods to retrieve the
corresponding elements from an array retrieved by getItems
methods.
List.js
var cocktail = require('cocktail'),
Enumerable = require('./Enumerable');
cocktail.mix({
'@exports': module,
'@as': 'class',
'@traits': [Enumerable],
'@properties': {
items: undefined
},
'@static': {
/* factory method*/
create: function(options) {
var List = this;
return new List(options);
}
},
constructor: function (options) {
this.items = options.items || [];
}
});
The List class uses the Enumerable Trait, the getItems is defined by the @properties
annotation.
index.js
var List = require('./List'),
myArr = ['one', 'two', 'three'],
myList;
myList = List.create({items: myArr});
console.log(myList.first()); // 'one'
console.log(myList.last()); // 'three'
Talents
Talents are very similar to Traits, in fact a Trait can be applied as a Talent in CocktailJS. The main difference is that a Talent can be applied to an object or module. So we can define a Talent as a Dynamically Composable Unit of Reuse (you can read more from this paper).
Using the Enumerable example, we can use a Trait as a Talent.
index.js
var cocktail = require('cocktail'),
enumerable = require('./Enumerable'),
myArr;
myArr = ['one', 'two', 'three'];
cocktail.mix(myArr, {
'@talents': [enumerable],
/* glue code for enumerable talent*/
getItems: function () {
return this;
}
});
console.log(myArr.first()); // 'one'
console.log(myArr.last()); // 'three'
We can also create a new Talent to define the getItems method for an Array to retrive the current instance.
ArrayAsItems.js
var cocktail = require('cocktail');
cocktail.mix({
'@exports': module,
'@as': 'class',
getItems: function () {
return this;
}
});
And then use it with Enumerable:
var cocktail = require('cocktail'),
enumerable = require('./Enumerable'),
arrayAsItems = require('./ArrayAsItems');
var myArr = ['one', 'two', 'three'];
cocktail.mix(myArr, { '@talents': [enumerable, arrayAsItems] });
console.log(myArr.first()); // 'one'
console.log(myArr.last()); // 'three'
Getting Started
- Install the module with:
npm install cocktail
or add cocktail to yourpackage.json
and thennpm install
- Start playing by just adding a
var cocktail = require('cocktail')
in your file.
Guides
Guides can be found at CocktailJS Guides
Documentation
The latest documentation is published at CocktailJS Documentation
Examples
A Cocktail playground can be found in cocktail recipes repo.
Contributing
In lieu of a formal styleguide, take care to maintain the existing coding style. Add unit tests for any new or changed functionality.
Running Lint & Tests
Add your unit and/or integration tests and execute
$ npm test
Run unit tests
$npm run unit
Run integration tests
$npm run integration
Lint your code
$ npm run lint
Before Commiting
Run npm test
to check lint and execute tests
$ npm test
Check test code coverage with instanbul
$ npm run coverage
Release History
see CHANGELOG
License
Copyright (c) 2013 - 2016 Maximiliano Fierro
Licensed under the MIT license.