Sample DI

main.js

const UserTypes = Object.freeze({
  DEFAULT: "DEFAULT",
  MANAGER: "MANAGER",
  ADMIN: "ADMIN",
});

class DefaultService {
  run() {
    console.log(DefaultService.name);
  }
}

class ManagerService {
  run() {
    console.log(ManagerService.name);
  }
}

class AdminService {
  run() {
    console.log(AdminService.name);
  }
}

class UserStrategySelector {
  strategies = new Map();

  constructor() {
    this.addStrategy(UserTypes.DEFAULT, DefaultService);
    this.addStrategy(UserTypes.MANAGER, ManagerService);
    this.addStrategy(UserTypes.ADMIN, AdminService);
  }

  addStrategy(transportType, strategy) {
    this.strategies.set(transportType, strategy);
  }

  getStrategy(transportType) {
    const strategy = this.strategies.get(transportType);

    if (!strategy) {
      throw new Error(`Strategy for ${transportType} not found`);
    }

    return new strategy();
  }
}

const userService = new UserStrategySelector();

userService.getStrategy(UserTypes.MANAGER).run();