如何使用属性方法克隆原型? [英] How to clone a prototype with property methods?
问题描述
我正在使用Typed.React库,该库包括一种将一个原型定义扩展为另一个原型定义的方法:
I am using the Typed.React library which includes a method to extend one prototype definition with that of another:
function extractPrototype(clazz) {
var proto = {};
for (var key in clazz.prototype) {
proto[key] = clazz.prototype[key];
}
return proto;
}
如果提供的类定义了属性方法,则此函数具有执行副作用get方法,例如
If the provided class defines property methods, this function has a side effect of executing the get method e.g.
var TestObject = (function () {
function TestObject() {
this.str = "test string";
}
Object.defineProperty(TestObject.prototype, "TestProperty", {
get: function () {
console.log("exec get");
return this.str;
},
set: function (value) {
console.log("exec set");
this.str = value;
},
enumerable: true,
configurable: true
});
return TestObject;
})();
var extracted = extractPrototype(TestObject);
当extactPrototype访问TestObject.prototype [ TestProperty]时,它将执行属性get方法并打印:
When extactPrototype accesses TestObject.prototype["TestProperty"], it will execute the property get method and print:
exec get
我如何在不执行属性方法的情况下复制原型?
How would I duplicate a prototype with property methods without executing them?
推荐答案
我认为您正在寻找新的ES6 Object。分配
函数。
I think you are looking for the new ES6 Object.assign
function.
当然,您的问题有一个更简单的解决方法-只是不访问和设置属性,复制它们的属性属性描述符:
Of course there's a simpler fix to your problem - just don't access and set properties, copy their property descriptors:
function extractPrototype(clazz) {
var proto = {};
for (var key in clazz.prototype) {
Object.defineProperty(proto, key, Object.getOwnPropertyDescriptor(clazz.prototype, key));
}
return proto;
}
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