我在玩功能装饰器。我想有一种方法可以轻松地装饰函数,而不必在声明函数的地方进行。
var __slice = [].slice;
this.around = function(decoration) {
return function(base) {
return function() {
var argv, callback, __value__,
_this = this;
argv = 1 <= arguments.length ? __slice.call(arguments, 0) : [];
__value__ = void 0;
callback = function() {
return __value__ = base.apply(_this, argv);
};
decoration.apply(this, [callback].concat(argv));
return __value__;
};
};
};
f("from outer");
function f(a){
console.log("f OUTER",a);
};
f("from outer");
(function g(){
f("from Inner (hoisted)");
function addDecorator(decoration, fn) {
var decorated = around(decoration)(fn);
eval(fn.name + " = decorated");
decorated.unDecorate = function (){
eval(fn.name + " = fn");
}
}
function myDecorator(cb){
console.log("before");
cb();
console.log("after");
}
function f(a){
console.log("f INNER",a);
}
f("from Inner (after declaration)");
addDecorator(myDecorator, f);
f("from Inner (Decorated)");
f.unDecorate();
f("from Inner (Undecorated)");
})();
f("from outer");
我希望能够addDecorator
在里面的任何地方打电话g
。即在f
其声明上方悬挂的顶部。
在 Chrome 的控制台中,我得到以下输出:
f OUTER from outer
f OUTER from outer
f INNER from Inner (hoisted)
f INNER from Inner (after declaration)
before
f INNER from Inner (Decorated)
after
f INNER from Inner (Undecorated)
f OUTER from outer
- 这可以在没有评估的情况下完成吗?
- addDecorator 可以移到 g 外吗?(没那么重要)