Convert array of employees to Dictionary

Question

So I'm using the LinqJS library to currently achieve the following:

    var allEmployees = [
        {
            "Id": 1374,
            "FirstName": "John",
            "LastName": "Doe"
        },
        {
            "Id": 1375,
            "FirstName": "Jane",
            "LastName": "Doe"
        }
    ];
    var employeeDictionary = Enumerable.from(allEmployees).toDictionary("$.Id", "$.FirstName+' '+$.LastName").toEnumerable().toArray();

When serializing employeeDictionary to JSON, I get the following format:

[
  {
    "key": 1374,
    "value": "John Doe"
  },
  {
    "key": 1375,
    "value": "Jane Doe"
  }
]

I do not want my data in this format, I wish to have it in this format:

{
  "1374": "John Doe",
  "1375": "Jane Doe"
}

I wrote something similar in PHP using YaLinqo which gives me the results I need:

echo json_encode(from($employees)->toDictionary('$v["Id"]', '$v["FirstName"]." ".$v["LastName"]')->toArray());

However, I would like to be able to achieve this in my JavaScript.

Answer 1

In JavaScript, an array is strictly always numerically indexed structure. So, .toArray abides with that. In PHP an array is closer to what JavaScript considers plain objects.

---

If using this LINQ JavaScript library

You can use the .toObject method to produce an object of your format - you need to pass in two functions - a key selector and a value selector, so the object gets built with the correct data:

var allEmployees = [
    {
        "Id": 1374,
        "FirstName": "John",
        "LastName": "Doe"
    },
    {
        "Id": 1375,
        "FirstName": "Jane",
        "LastName": "Doe"
    }
];
var employeeDictionary = Enumerable.from(allEmployees)
  .toDictionary("$.Id", "$.FirstName+' '+$.LastName")
  .toEnumerable()
  .toObject(entry => entry.key, entry => entry.value);

/* output:
{
  "1374": "John Doe",
  "1375": "Jane Doe"
}
*/

Using destructuring, the key/value selectors can be transformed to:

.toObject(({key}) => key, ({value}) => value);

---

If using this library for LINQ operations, then you need to slightly change the syntax:

var allEmployees = [
    {
        "Id": 1374,
        "FirstName": "John",
        "LastName": "Doe"
    },
    {
        "Id": 1375,
        "FirstName": "Jane",
        "LastName": "Doe"
    }
];
var employeeDictionary = Enumerable.From(allEmployees)
  .ToDictionary("$.Id", "$.FirstName+' '+$.LastName")
  .ToEnumerable()
  .ToObject("$.Key", "$.Value");

/* output:
{
  "1374": "John Doe",
  "1375": "Jane Doe"
}
*/