class SingletonDefaultExportInstance {
  constructor() {
    this._type = 'SingletonDefaultExportInstance';
  }

  singletonMethod() {
    return 'singletonMethod';
  }

  static staticMethod() {
    return 'staticMethod';
  }

  get type() {
    return this._type;
  }

  set type(value) {
    this._type = value;
  }
}

export default new SingletonDefaultExportInstance();

// ...

// index.js
import SingletonDefaultExportInstance from './SingletonDefaultExportInstance';

// Instantiate
// console.log(new SingletonDefaultExportInstance);  // is not a constructor

// Prototype Method
console.log(SingletonDefaultExportInstance.type, SingletonDefaultExportInstance.singletonMethod());

// Getter/Setter
SingletonDefaultExportInstance.type = 'type updated';
console.log(SingletonDefaultExportInstance.type);

// Static method
console.log(SingletonDefaultExportInstance.constructor.staticMethod());