How to Deconstruct objects in C# like we do in Javascript

April 8th, 2021 1 Minutes

c#
javascript
deconstruction
syntax
.net

I've been using C# for about a decade now, and every now and again I discover something that surprises me. This week it's the ability to deconstruct as we do in Javascript (and I'm not talking about using Tuples!).

Below is a simple example of deconstruction taking place to draw out the power, and defence property for our Trex object,

const trex = {
    statistics: {
        power: 10,
        defence: 2
    },
    name: "T-Rex", 
};

const { power, defence } = trex.statistics;

console.log(`Power ${power}, Defence ${defence}`);
//Power 10, Defence 2

//Better than doing:
//const power = trex.statistics.power;
//const defence = trex.statistics.defence;

As Mozilla's definition states,

The destructuring assignment syntax is a JavaScript expression that makes it possible to unpack values from arrays, or properties from objects, into distinct variables - Destructuring assignment.

It's a powerful syntactical sugar, especially in the scenarios where you have a nested object with long names. As deconstruction can lead to cleaner, more readable code its uses are great on large object types. Now let's take a look at the same thing but in C#,

namespace deconstruction
{
    public record Statistics(int Power, int Defence);

    public class Trex
    {
        public Statistics Statistics;
        public string Name;

        public Trex()
        {
            Name = "T-Rex";
            Statistics = new Statistics(10, 5);
        }

        // Return the first and last name.
        public void Deconstruct(out int power, out int defence)
        {
            power = Statistics.Power;
            defence = Statistics.Defence;
        }
    }
}

Ok admittedly it's not as elegant as its Javascript counterpart as we need to define what we want to deconstruct upfront as well as have a function for each combination 😬! but it's still got its uses... check it out,

using System;

namespace deconstruction
{
    class Program
    {
        static void Main(string[] args)
        {
            var trex = new Trex();
            var (power, defence) = trex;

            Console.WriteLine($"Power: {power}, Defence: {defence}");
            //Power: 10, Defence: 5

            //Better than doing:
            //var power = trex.statistics.power;
            //var defence = trex.statistics.defence;
        }
    }
}

Who knows what other hidden gems 💎 lie buried with the Microsoft docs!

.NET & GRPC What they forgot to tell you

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