With this new functionality the value of the environment variable can be retrieved through the indexer:

var reader = new EnvReader();
var key1 = reader["KEY1"];
var key2 = reader["KEY2"];

The advantage of this is that you can use dependency injection, either manually or by using a service container such as Microsoft.Extensions.DependencyInjection.

For example:

class ExampleController
{
    private IEnvReader reader;
	
    public ExampleController(IEnvReader reader)
    {
         this.reader = reader;
    }
	
    public void MethodExample()
    {
         var key1 = reader["KEY1"];
         var key2 = reader["KEY2"];
    }
}

The IEnvReader interface also has some auxiliary methods to retrieve the value of an environment variable in a specific format (integer, double, etc.) and warns the client when it does not find the variable. It is true that currently the library already has this functionality but it does not warn the client when it does not find an environment variable.

Methods that do not start with Try (as GetBoolValue, etc.) throw an exception when the environment variable is not found. Methods that start with Try (as TryGetBoolValue), however, return false if the variable is not found, so the client has two options for handling the error.