Inversify.js - Reflect.hasOwnMetadata is not a function

It seems you will need to include the reflect-metadata package. Try adding an import to it in inversify.config.ts by doing:

import "reflect-metadata";

May be a silly thing to point out, I ran into a the same issue but it was because of the order of imports. Its unlikely to be the case for any other imports but in case of reflect-metadata it has to be imported before any classes that use it.

import { Container } from "inversify";
//reflect-metadata should be imported 
//before any interface or other imports
//also it should be imported only once
//so that a singleton is created.
import "reflect-metadata";
import Battle from "./interfaces/battle";
import EpicBattle from "./interfaces/epic_battle";