JavaScript：如何在不使用new关键字的情况下创建类的新实例？ [英] JavaScript: How to create a new instance of a class without using the new keyword?

问题描述

我认为以下代码会使问题清楚。

I think the following code will make the question clear.

// My class
var Class = function() { console.log("Constructor"); };
Class.prototype = { method: function() { console.log("Method");} }

// Creating an instance with new
var object1 = new Class();
object1.method();
console.log("New returned", object1);

// How to write a factory which can't use the new keyword?
function factory(clazz) {
    // Assume this function can't see "Class", but only sees its parameter "clazz".
    return clazz.call(); // Calls the constructor, but no new object is created
    return clazz.new();  // Doesn't work because there is new() method
};

var object2 = factory(Class);
object2.method();
console.log("Factory returned", object2);

推荐答案

这不行吗？

function factory(class_) {
    return new class_();
}

我不明白为什么不能使用 new 。

I don't understand why you can't use new.

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