groupJoin produces empty result when inner is empty

[XC-Zhang]

groupJoin produces empty result when inner is empty. Let's see the following example.

const Enumerable = require("node-enumerable");

const persons = [
  { name: "Tanja" },
  { name: "Marcel" },
  { name: "Yvonne" },
  { name: "Josefine" }
];

const pets = [];

const e = Enumerable.from(persons)
  .groupJoin(
    pets, 
    person => person.name, 
    pet => pet.owner.name,
    (person, pets) => { person, pets }
  )
  .toArray();

Online runner
The example will result in an empty array [].

Expected result would be:

[
  { person: { name: "Tanja" }, pets: [] },
  { person: { name: "Marcel" }, pets: [] },
  { person: { name: "Yvonne" }, pets: [] },
  { person: { name: "Josefine" }, pets: [] }
]

Corresponding C# code produces the expected result.

using System;
using System.Collections.Generic;
using System.Linq;

public class Program
{
  public static void Main()
  {
    var people = new Person[]
    {
      new Person("Tanja"),
      new Person("Marcel"),
      new Person("Yvonne"),
      new Person("Josefine")
    };

    var pets = new Pet[0];

    var e = people.GroupJoin(
      pets, 
      person => person.Name, 
      pet => pet.Owner.Name,
      (person, ps) => new { Person = person, Pets = ps }
    ).ToArray();
  }
}

public class Person
{
  public string Name { get; set; }
  public Person(string name)
  {
    Name = name;
  }
}

public class Pet
{
  public string Name { get; set; }
  public Person Owner { get; set; }
  public Pet(string name, Person owner)
  {
    Name = name;
    Owner = owner;
  }
}