节点js的奇怪错误：TypeError X不是构造函数

Question

Anyone know why this is happening?

I have a pretty complex system so to simplify it we have this code:

profile_manager.js

const Profile = require('./profile');

class ProfileManager {
  doThing() {
    const prf = new Profile("Lemon", "ade");
  }
}
const prfManager = new ProfileManager();
module.exports = prfManager;

profile.js

class Profile {
  constructor(arg0, arg1) {
    //do thing
  }
}

module.exports = Profile;

index.js

const prfManager = require('./profile_manager');
prfManager.doThing();

Once.doThing() is called, I get a TypeError saying that "Profile is not a constructor".

HOWEVER... When I change profile_manager.js to the following code below, it works perfectly. No TypeError.

class ProfileManager {
  doThing() {
    const Profile = require('./profile');
    const prf = new Profile("Lemon", "ade");
  }
}
const prfManager = new ProfileManager();
module.exports = prfManager;

I even console.logged the prf object and it works the way I want it to. Why does it only work when I move the "const Profile = require('./profile');"within the method but when I put it at the top of the module, it does not want to work.

Answer 1

I found out that profile.js had an instance of profile_manager.js or something like that

This post talks more about it How to deal with cyclic dependencies in Node.js