Javascript私有函数和object.prototype扩展
我有以下angularJS服务Javascript私有函数和object.prototype扩展,javascript,angularjs,prototype,extend,Javascript,Angularjs,Prototype,Extend,我有以下angularJS服务 define(["angular"], function(Angular) { var dataStorageService = function() { var serviceConstructor = function() { var _getColor = function(color) { return this.config.categoryColorMapping.colors[color];
define(["angular"], function(Angular) {
var dataStorageService = function() {
var serviceConstructor = function() {
var _getColor = function(color) {
return this.config.categoryColorMapping.colors[color];
}
}
var serviceInstance = new serviceConstructor();
angular.extend(serviceInstance.prototype, {
config: {
numberOfMessagesDisplayed: 5,
maxTitleLength: 48,
maxPreambleLength: 140,
categoryColorMapping: {
colors : {
nyheter: '#2B2B2B',
sport: '#F59331',
underholding: '#F9B00D'
},
categories: {
nyheter: _getColor('nyheter'),
sport: _getColor('sport'),
underholding: _getColor('underholding')
}
}
},
get: function(param) {
if(this.config.hasOwnProperty(param)) {
return this.config[param];
} else {
console.warn('Playlist::configService:no "' + param + '" config found');
return false;
}
},
set: function(param, value) {
this.config[param] = value;
}
});
return serviceInstance;
};
return dataStorageService;
});
现在我的目标是公开以下方法:
这样做有可能吗?(要在angular.extend内的JSON对象中使用_GetColorPrivate?添加到
原型的函数在构造函数的词法范围之外定义,因此无法访问“private”方法
前者在所有实例之间共享,后者在每个实例之间共享。解决此问题的唯一方法是将(每个实例)函数显式导出为实例的属性,使其非私有。在服务构造函数的定义中
在的定义后添加以下行
serviceConstructor.prototype._getColor = _getColor ;
函数可以共享,但仍然是私有的,但必须在构造函数中定义特定于实例的私有成员。由于您的私有函数不需要访问特定于实例的私有成员,因此您可以执行以下操作:
define(["angular"], function(Angular) {
var dataStorageService = function() {
var serviceConstructor = function() {
}
var serviceInstance = new serviceConstructor();
//IIFE returning object that will have private members as closure
// privileged methods have to be in the same function body as the
// private fucnction
serviceInstance.prototype = (function() {
var _getColor = function(instance, color) {
return instance.config.categoryColorMapping.colors[color];
};
return {
constructor: serviceConstructor
,config: {
numberOfMessagesDisplayed: 5,
maxTitleLength: 48,
maxPreambleLength: 140,
categoryColorMapping: {
colors : {
nyheter: '#2B2B2B',
sport: '#F59331',
underholding: '#F9B00D'
},
categories: {
//since categories is a sub object of serviceinstance.categorycolormapper
// it is not possible to get the instance of serviceinstance
// at this time unless you set it in the constructor
// solution could be that each serviceinstance has it's own categorycolormaper
// and when categorycolormapper is created pass the serviceinstance instance
nyheter: _getColor(this,'nyheter'),
sport: _getColor(this, 'sport'),
underholding: _getColor(this, 'underholding')
}
}
},
get: function(param) {
if(this.config.hasOwnProperty(param)) {
return this.config[param];
} else {
console.warn('Playlist::configService:no "' + param + '" config found');
return false;
}
},
set: function(param, value) {
this.config[param] = value;
}
}
}());
return serviceInstance;
};
return dataStorageService;
});
有关构造函数和原型的更多信息,请参见此处:每次创建新实例时,每个实例都将引用该特定实例的函数版本,并且该函数只能访问该实例的其他私有变量和方法。使用dataStorageService中声明的任何引用变量作为通道来获取_getColor的可用性//数据存储服务。。。var internal={};//。。。在构造函数内部。\u getColor=\u getColor;当您将原型设置为on IIFE的返回值时,可以添加私有方法。方法不是特定于实例的,因此它是可能的。特定于实例的成员需要在构造函数中定义,所有需要访问它们的特权方法也是如此。还有其他模式可以模拟,例如: