Circular dependency Super expression must either be null or a function

Question

We have circular depenency structure that should be fine logically. Light imports Node which imports NodeManager which inturn imports Light. When running our code we get the following

"Super expression must either be null or a function"

NodeManager

// in NodeManager.js
import Light from '../../Light.js'

class NodeManager {
  static _instance;
  static getInstance() {
    if(NodeManager._instance === undefined) {
      NodeManager._instance = new NodeManager();
    }
   return NodeManager._instance;
  }
  ...
  addNode(node){
    ...
    if(node instanceOf Light){
      ...
    }
    ...
  }
}

Node

// in Node.js
import NodeManager from '../../NodeManager.js'
class Node {
  constructor() {
    ...
    NodeManager.instance().addNode(this);
    ...
  }
}

Light

// in Light.js
import Node from '../../Node.js'
class Light extends Node {
  constructor() {
    super();        
    ...
  }
}

For some reason the import of Node in light does not work thus Light.js throws the error when calling super. I am uncertain of how to solve this. Any help is appreciated.

have you solved it? struggling with the same thing. – vir us Dec 18 '20 at 10:00 — vir us, Dec 18 '20 at 10:00

score 0 · Answer 1 · answered Aug 08 '17 at 11:55

0

super() must be the first thing you call in the constructor (see here). It seems like you're missing super() call in the constructor of the Node class.

answered Aug 08 '17 at 11:55

matmiz

70
9

No I call super I just left it out for brevity. – Pablo Jomer Aug 08 '17 at 14:03

Circular dependency Super expression must either be null or a function

1 Answers1