Classy.js

Small and simple Javascript class creator, supporting multiple inheritance.

Supported browsers (i.e. tested in)

• Firefox 7
• Chrome 15
• Opera 11.52 / Opera Mobile 9.80
• Android 2.3 browser (probably Safari 4.0)
• Internet Explorer 9

Unit tests

Pull submodules (git submodule update --init) and open tests/index.html in your favorite browser.

Usage

1. Create simple class:

Test = Classy({
	a: null
});

obj1 = new Test();
obj1.a = 1;

obj2 = new Test();
obj2.a = 2;

// obj1.a == 1
// obj2.a == 2

2. Create class with initializer (constructor):

Test = Classy({
	a: null,
	init: function(a) {
		this.a = a;
	}
});

obj1 = new Test(1);
obj2 = new Test(2);

// obj1.a == 1
// obj2.a == 2

3. Create class with inheritance (class ExtendedTest extends Test)

Test = Classy({
	a: null,
	init: function(a) {
		this.a = a;
	}
});

ExtendedTest = Classy(Test, {
	b: null,
	init: function(a, b) {
		this.a = a;
		this.b = b;
	}
});

obj = new ExtendedTest(1, 2);

// obj1.a == 1
// obj2.a == 2

4. Check inheritance:

obj = new ExtendedTest(1, 2);

// obj instanceof Test == true
// obj.instanceOf(Test) == true
// Test.parentOf(obj) == true
// Test.parentOf(Test) == true
// Test.parentOf(ExtendedTest) == true

// obj instanceof ExtendedTest == true
// obj.instanceOf(ExtendedTest) == true
// ExtendedTest.parentOf(obj) == true

Note: instanceof doesn't work for multiple inheritance (is unreliable), instead use object.instanceOf(Class) or Class.parentOf(object)

5. Create class with multiple inheritance:

Base1 = Classy({
	a: 1,
	m: function() {
		return this.a;
	}
});

Base2 = Classy({
	b: 2,
	m: function() {
		return this.b;
	}
});

Test = Classy(Base1, Base2, {});
// or
Test = Classy([Base1, Base2], {});

obj = new Test();

// obj.m() == 2

6. Check multiple inheritance:

Base1 = Classy({});

Base2 = Classy({});

Test = Classy(Base1, Base2, {});

obj = new Test();

// obj.instanceOf(Test) == true
// obj.instanceOf(Base1) == true
// obj.instanceOf(Base2) == true

// Base1.parentOf(obj) == true
// Base2.parentOf(obj) == true
// Test.parentOf(obj) == true

// Base1.parentOf(Test) == true
// Base2.parentOf(Test) == true

// obj instanceof Test == true
// obj instanceof Base2 == true
// obj instanceof Base1 == false, read note in example 4.

7. Access overloaded method:

Base1 = Classy({
	a: 1,
	m: function() {
		return this.a;
	}
});

Base2 = Classy({
	b: 2,
	m: function() {
		return Base1.m(this)();
	}
});

Test = Classy(Base1, Base2, {});

obj = new Test();

// obj.m() == 1
// Base1.m(obj)() == 1

• Base1.m(this)(arg1, arg2) is equivalent for Base1.fn.m.call(this, arg1, arg2)
• Base1.fn is equivalent for Base1.prototype (jQuery style)

Inspired by

• John Resig's Simple Class