RequireJS技术疑问：实例化后的对象存储位置在哪里？

Hey there! Let's tackle your RequireJS questions clearly—this stuff can feel opaque at first, but once you understand how the module system works, it clicks.

1. Where does RequireJS store objects? #

When RequireJS loads a module for the first time, it caches the module's exported value in an internal storage object. Specifically, you can find cached modules in require.s.contexts._.defined.

Each key in this object is the module ID you used to load the module, and the value is whatever the module exported (could be an object, function, class instance, or primitive). For example, if you load a module named userService, you can check its cached value with:

console.log(require.s.contexts._.defined['userService']);

This cache is maintained entirely by RequireJS—you almost never need to modify it directly, but it’s super useful for debugging when you’re trying to track down where a module’s value lives.

2. Can't find an instantiated object—where is it stored? #

This depends entirely on how you created and exposed the instance. Let’s break down common scenarios:

• The instance is the module's exported value:
  If your module looks like this:

  // userModel.js
  define(function() {
    class User {
      constructor(name) { this.name = name; }
    }
    // Export an instantiated User directly
    return new User('Alice');
  });
  

  Then this instance lives in RequireJS’s cache at require.s.contexts._.defined['userModel']. You can access it by requiring the module normally:

  require(['userModel'], function(userInstance) {
    console.log(userInstance.name); // Logs "Alice"
  });
  

• The instance is a private variable inside the module:
  If you created an instance but didn’t export it directly, it’s locked inside the module’s closure and can’t be accessed from outside—unless you expose it via an exported method. For example:

  // authService.js
  define(function() {
    class Auth {
      login() { /* ... */ }
    }
    // Private instance (not exported directly)
    const authInstance = new Auth();
  
    // Export a method to get the instance
    return {
      getAuthInstance: function() {
        return authInstance;
      }
    };
  });
  

  To access this instance, you’d call the exported method:

  require(['authService'], function(authService) {
    const instance = authService.getAuthInstance();
    instance.login();
  });
  

• You instantiated the object outside a module:
  If you created the instance in a global scope (not recommended with RequireJS) or a local function scope, RequireJS doesn’t track it. Global instances in browsers live on the window object, while local instances are only accessible within their own scope.

A quick best practice: Stick to RequireJS’s modular pattern—export only what you need, and avoid global variables. This makes tracking instances way easier!

内容的提问来源于stack exchange，提问作者Langerz