我正在开发一个类似于elFinder的文件管理器框架。我当前的代码工作正常但现在我想让它看起来更好并添加链接(我不确定它是链接还是装饰模式)。
以下是我想要做的一个示例:
function UI() {}
UI.prototype.folders = function(){
return [];
}
UI.prototype.folders.prototype.getSelectedFolder = function(){
return {};
}
调用UI.folders()
应该返回一个文件夹对象数组。所以如果你打电话给UI.folders()
,你会得到类似的东西:
[
Object { name="folder1", selected=false },
Object { name="folder2", selected=false },
Object { name="folder3", selected=true }
]
调用UI.folders().getSelectedFolder()
会过滤UI.folders()
的结果并返回:
Object { name="folder3", selected=true }
这可能吗?在这种情况下说“链接”还是“装饰图案”是正确的吗?
如果不是 - 还有另一种更合适的方法吗?
非常感谢任何帮助!
答案 0 :(得分:2)
你问题中的代码并不反映正确的实施,而是回答你的直接问题,是的,这......
UI.folders().getSelectedFolder()
...将是方法链的一个例子。
装饰图案不同。如果你有一组方法,并且每个方法应该总是首先调用一些常用函数,你可以创建一个装饰器,它将返回一个首先调用公共函数的函数,然后是实际函数...
function foo() {
console.log('I\'m foo, and I\'m first, and I was given these args:', arguments);
}
function decorateWithFoo(decorated) {
return function () {
foo.apply(this, arguments);
decorated.apply(this, arguments);
};
}
因此,您可以使用decorateWithFoo
创建一个始终首先调用foo
的函数...
// create and decorate bar()
var bar = function(a,b) {
console.log('I\'m bar, and I was called after "foo", and was given args:', a, b);
};
bar = decorateWithFoo(bar);
bar(123, 456); // this will first call `foo()`, then (the original) `bar()`.
// create and decorate baz()
var baz = function(a,b) {
console.log('I\'m baz, and I was called after "foo", and was given args:', a, b);
};
baz = decorateWithFoo(baz);
baz(123, 456); // this will first call `foo()`, then (the original) `baz()`.
有些语言内置了用于创建装饰器的语法。 JavaScript目前没有。
如果你发现自己以不同的方式使用装饰器,你可以创建另一个设置初始装饰器功能的函数......
function generateDecorator(decorator) {
return function (decorated) {
return function () {
decorator.apply(this, arguments);
decorated.apply(this, arguments);
};
};
}
所以原来的decoreateWithFoo
可能就像这样设置......
function foo() {
console.log('I\'m foo, and I\'m first, and I was given these args:', arguments);
}
var decorateWithFoo = generateDecorator(foo);
答案 1 :(得分:1)
为了使其正常工作,您需要使您的folder方法成为一个返回从数组继承的对象的函数。:
UI.prototype.folders = function(){
// must return an object that inherits from an array
// that has the additional methods on it you want like getSelectedFolder()
}
答案 2 :(得分:0)
有几种不同的方法可以解决这个问题。主要目标是当你调用一个函数时,你会得到一个对象/函数,它是具有不同属性的相同类型的对象。我不喜欢原型用法,所以我会这样做(这是解决它的一种方法):
var FolderList = function ()
{
var _folders = [];
folders.pop({ name: "folder1", selected: false });
folders.pop({ name: "folder2", selected: true });
folders.pop({ name: "folder3", selected: false });
// prevent other programers from changing _folders
// which would break this, so just use a function
this.folders = function ()
{
return _folders;
}
this.selectedFolders = function ()
{
var tmpFolders = [];
for (var folderIndex = 0;
folderIndex < this._folders.length;
folderIndex++)
{
if (this._folders[folderIndex].selected)
{
tmpFolders.pop(_folders[folderIndex]);
}
}
_folders = tmpFolders;
return this;
}
this.addFolder = function (folder)
{
_folders.pop(folder);
return this;
}
};
var folderList = new FolderList();
folderList.selectedFolders()
.addFolder({ name: "folder1", selected: false })
.addFolder({ name: "folder3", selected: true })
.selectedFolders();
// array of 2 objects, folder2 and folder3
var arrayOfSelectedFolder = folderList.folders();