获取类构造函数参数名称 [英] Get class constructor argument names

问题描述

我正在为ES类实现某种依赖注入解决方案，为此，我需要知道类构造函数参数的确切名称.

I'm implementing a certain dependency injection solution for ES classes, and for it I need to know exact names of class constructor parameters.

当我得到类或类静态方法的字符串形式时，它确实给出了完整的代码(通常对于函数而言)，但是对于类构造函数却没有.

When I get string form of class or class static method, it does give full code (as usually for functions), but for class constructor it does not.

class C { constructor(a, b) { }; static m(x,y) { } }
console.log(C);
console.log(C.constructor);
console.log(C.m);

产生

class C { constructor(a, b) { }; static m(x,y) { } }
ƒ Function() { [native code] }
ƒ m(x,y) { }

结果，我必须解析整个类代码以使用正则表达式提取构造器参数部分

As result, I have to parse whole class code to extract constructor arguments part, using regex like this

C.toString().split(/constructor\s*[^\(]*\(\s*([^\)]*)\)/m)

是否有更干净的方法来获取构造函数参数名称?

Is there any cleaner way to get constructor argument names?

更新: 感谢您的所有意见和评论，但是我非常清楚缩小的工作原理，TS装饰器的工作方式以及Angular/AngularJS DI的实现方式以及工作方式.它与问题无关.问题是:

Update: Thank you for all your opinions and comments but I'm crystal aware how minification works, how TS decorators work and how Angular/AngularJS DI is implemented and how it works. It is not related to the question. The question is:

是否可以获取构造函数代码，因为函数可以使用?

推荐答案

不应该将参数的名称视为标识要注入到constructor中的内容的可靠方法.如您所见，JavaScript并非旨在让您以适当的方式检索这些名称，并且如果您在浏览器环境中，则可能在释放代码之前将代码缩小了，从而导致名称丢失.

A parameter's name should not be considered as a reliable way to identify what to inject into a constructor. As you noticed, JavaScript is not designed to let you retrieve these names in a proper way, and if you're in a browser context, you're probably minifying the code before releasing it, causing the loss of the names.

JavaScript中的依赖注入机制通常依赖于元数据，例如Angular的元数据.它使用TypeScript装饰器将排序后的参数 types 存储在Map中，该键的键是类本身，而值是类的Array.然后，可以通过简单的引用比较(或instanceof)来检查可注入对象池中是否已实例化了所需的类.

Dependency injection mechanisms in JavaScript usually rely on metadata, such as Angular's one. It uses TypeScript decorators to store the ordered parameters types in a Map whose the key is the class itself, and the value is an Array of classes. Then, it's possible to check if a required class has already been instantiated in your pool of injectable objects thanks to a simple reference comparison (or instanceof).

FYI回送是另一个使用TypeScript和依赖项注入的后端框架(在Node.js中运行).

FYI Loopback is another backend framework (running in Node.js) that uses TypeScript and dependency injection.

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