node.js 中的覆盖方法 [英] Overriding method in node.js

问题描述

我正在寻找覆盖自定义模块 node.js 中方法的最佳方法.

i'm looking for the best way to overrid a method in a custom module node.js.

我正在开发一个自定义中间件，它将帮助我自动加载一些自定义模块.像安全，用户等...

I'm working on a custom middleware who will help me to automatically load some custom module. Like security, users etc...

但如果我需要自定义安全检查之类的东西，我希望能够覆盖某些方法.目前我发现的唯一方法是导出一个函数，该函数将替换我的方法并公开上下文变量.

But i want to be able to override some methods if i need something like a custom security hand check. For now the only way i found is to export a function who will replace my method and expose context variables.

// CUSTOM MODULE EXAMPLE
// ========================================

var myVar = "Hello ";
var myVar2 = "!";

var method = function() {
  return "world" + myVar2;
}

module.exports.loadModule = function() {
   console.log(myVar + method());
};

module.exports.overrideMethod = function(customMethod) {
  method = customMethod;
};

module.exports.myVar2 = myVar2;

我的主应用程序将是这样的:

And my main app will be like that:

// MAIN APP EXAMPLE
// ========================================

var myCustomModule = require('customModule.js');

myCustomModule.overrideMethod(function() {
   return "viewer" + myCustomModule.myVar2;
});

myCustomModule.loadModule(); 

你怎么看?我走得好吗?

What do you think? Am i on the good way?

感谢阅读.汤姆

推荐答案

通常，我将任何具有可变全局状态的模块视为错误.相反，我会选择使用这些方法创建一个对象并有一种方法来传递覆盖.

Generally I treat any module that has mutable global state like this to be a mistake. Instead, I'd opt for creating an object with these methods and having a way to pass in overrides.

// CUSTOM MODULE EXAMPLE
// ========================================

var DEFAULT_PREFIX = "Hello ";
var DEFAULT_SUFFIX = "!";


var DEFAULT_METHOD = function() {
  return "world" + DEFAULT_SUFFIX;
};

module.exports = function(options){
    var method = options.method || DEFAULT_METHOD

    return {
        loadModule: function(){
            console.log(myVar + method());
        }
    };
};

module.exports.DEFAULT_SUFFIX = DEFAULT_SUFFIX;

然后你可以这样使用:

// MAIN APP EXAMPLE
// ========================================

var myCustomModule = require('customModule.js');

var loader = myCustomModule({
    method: function() {
        return "viewer" + myCustomModule.DEFAULT_SUFFIX;
    }
});

loader.loadModule(); 

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