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index.js
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index.js
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/**
* jclass v1.1.9
* https://github.com/riga/jclass
*
* Marcel Rieger, 2015
* MIT licensed, http://www.opensource.org/licenses/mit-license
*/
(function(factory) {
/**
* Make jclass available in any context.
*/
if (typeof(define) == "function" && define.amd) {
// AMD
define([], factory);
} else if (typeof(exports) == "object") {
// CommonJS
exports = factory();
if (typeof(module) == "object") {
// NodeJS
module.exports = exports;
}
} else if (window) {
// Browser
window.JClass = factory();
} else if (typeof(console) == "object" && console.error instanceof Function) {
// error case
console.error("cannot determine environment");
}
})(function() {
/**
* Helper functions.
*/
/**
* Checks whether a passed object is a function.
*
* @param obj - The object to check.
* @returns {boolean}
*/
var isFn = function(obj) {
return obj instanceof Function;
};
/**
* Extends a target object by one or more source objects with shallow key comparisons. Note that
* the extension is done in-place.
*
* @param {object} target - The target object to extend.
* @param {...object} source - Source objects.
* @returns {object} The extended object.
*/
var extend = function(target) {
var sources = Array.prototype.slice.call(arguments, 1);
// loop through all sources
for (var i in sources) {
var source = sources[i];
// object check
if (typeof(source) != "object") {
continue;
}
// loop through all source attributes
for (var key in source) {
target[key] = source[key];
}
}
return target;
};
/**
* Default options.
*/
var defaultOptions = {
// internal object for indicating that class objects don't have a class object themselves,
// may not be used by users
_isClassObject: false
};
/**
* Flags.
*/
// flag to distinguish between prototype and class instantiation
var initializing = false;
/**
* Base class definition.
*/
// empty BaseClass implementation
var BaseClass = function(){};
// add the _subClasses entry
BaseClass._subClasses = [];
// empty init method
BaseClass.prototype.init = function(){};
/**
* Extend mechanism. Returns a derived class.
*
* @param {object} instanceMembers - Members that will be owned by instances.
* @param {object} classMembers - Members that will be owned by the class itself.
* @returns {JClass}
*/
BaseClass._extend = function(instanceMembers, classMembers, options) {
// default arguments
if (instanceMembers === undefined) {
instanceMembers = {};
}
if (classMembers === undefined) {
classMembers = {};
}
if (options === undefined) {
options = {};
}
// mixin default options
options = extend({}, defaultOptions, options);
// sub class dummy constructor
var JClass = function() {
// nothing happens here when we are initializing
if (initializing) {
return;
}
// store a reference to the class itself
this._class = JClass;
// all construction is actually done in the init method
if (this.init instanceof Function) {
this.init.apply(this, arguments);
}
};
// alias for readability
var SuperClass = this;
// create an instance of the super class via new
// the flag sandwich prevents a call to the init method
initializing = true;
var prototype = new SuperClass();
initializing = false;
// get the prototype of the super class
var superPrototype = SuperClass.prototype;
// the instance of the super class is our new prototype
JClass.prototype = prototype;
// enforce the constructor to be what we expect
// calls to the constructor will invoke the init method (see above)
JClass.prototype.constructor = JClass;
// store a reference to the super class
JClass._superClass = SuperClass;
// store references to all extending classes
JClass._subClasses = [];
SuperClass._subClasses.push(JClass);
// make this class extendable as well
JClass._extend = SuperClass._extend;
// _extends returns true if the class itself extended "target"
// in any hierarchy, e.g. every class extends "JClass" itself
JClass._extends = function(target) {
// this function operates recursive, so stop when the super class is our BaseClass
if (this._superClass == BaseClass) {
return false;
}
// success case
if (target == this._superClass || target == BaseClass) {
return true;
}
// continue with the next super class
return this._superClass._extends(target);
};
// propagate instance members directly to the created protoype,
// the member is either a normal member or a descriptor
for (var key in instanceMembers) {
var property = Object.getOwnPropertyDescriptor(instanceMembers, key);
var member = property.value;
// descriptor flag set?
if (member !== null && typeof(member) == "object" && member.descriptor) {
Object.defineProperty(prototype, key, member);
// getter/setter syntax
} else if (!("value" in property) && ("set" in property || "get" in property)) {
Object.defineProperty(prototype, key, property);
// normal member, simple assignment
} else {
prototype[key] = member;
// if both member and the super member are distinct functions
// add the super member to the member as "_super"
var superMember = superPrototype[key];
if (isFn(member) && isFn(superMember) && member !== superMember) {
member._super = superMember;
}
}
}
// propagate class members to the _members object
if (!options._isClassObject) {
// try to find the super class of the _members object
var ClassMembersSuperClass = SuperClass._members === undefined ?
BaseClass : SuperClass._members._class;
// create the actual class of the _members instance
// with an updated version of our options
var opts = extend({}, options, { _isClassObject: true });
var ClassMembersClass = ClassMembersSuperClass._extend(classMembers, {}, opts);
// store the actual JClass in ClassMembersClass
ClassMembersClass._instanceClass = JClass;
// create the _members instance
JClass._members = new ClassMembersClass();
}
// return the new class
return JClass;
};
/**
* Converts arbitrary protoype-style classes to our JClass definition.
*
* @param {function} cls - The class to convert.
* @returns {JClass}
*/
BaseClass._convert = function(cls, options) {
// the properties consist of the class' prototype
var instanceMembers = cls.prototype;
// add the constructor function
instanceMembers.init = function() {
// simply create an instance of our target class
var origin = this._origin = BaseClass._construct(cls, arguments);
// add properties for each own property in _origin
Object.keys(origin).forEach(function(key) {
if (!origin.hasOwnProperty(key)) {
return;
}
Object.defineProperty(this, key, {
get: function() {
return origin[key];
}
});
}, this);
};
// finally, create and return our new class
return BaseClass._extend(instanceMembers, {}, options);
};
/**
* Returns an instance of a class with a list of arguments. This provides an apply-like
* constructor usage. Note that this approach does not work with native constructors (e.g. String
* or Boolean).
*
* @param {Class|JClass} cls - The class to instantiate. This may be a JClass or a prototype-based
* class.
* @param {array} [args=[]] - Arguments to pass to the constructor.
* @returns {instance}
*/
BaseClass._construct = function(cls, args) {
// empty default args
if (args === undefined) {
args = [];
}
// create a class wrapper that calls cls like a function
var Class = function() {
return cls.apply(this, args);
};
// copy the prototype
Class.prototype = cls.prototype;
// return a new instance
return new Class();
};
/**
* Returns a property descriptor of the super class.
*
* @param {JClass|instance} cls - A JClass or an instance of a JClass to retrieve the property
* descriptor from.
* @param {string} prop - The name of the property descriptor to get.
* @returns {object}
*/
BaseClass._superDescriptor = function(cls, prop) {
// if cls is an instance, use its class
if ("_class" in cls && cls instanceof cls._class) {
cls = cls._class;
}
// a JClass?
if ("_extends" in cls && cls._extends instanceof Function && cls._extends(this)) {
return Object.getOwnPropertyDescriptor(cls._superClass.prototype, prop);
} else {
return undefined;
}
};
/**
* Return the BaseClass.
*/
return BaseClass;
});