RCi.ErrorAsValue

.NET Error as value package

Usage:

Consider this example:

public sealed record Employee(string FirstName, string LastName, int Age); private static readonly Dictionary<int, Employee> _employees = new() { { 0, new("Michael", "Smith", 35) }, { 1, new("Kenji", "Tanaka", 25) }, { 2, new("Andrew", "Martinez", 50) }, { 3, new("Emily", "Johnson", 28) }, { 4, new("Jamal", "Washington", 30) }, }; private static Ve<Employee> GetEmployeeById(int id) { if (_employees.TryGetValue(id, out var employee)) { return employee; } return Error.NewNotFound("cannot find employee by id", (nameof(id), id)); }

Try to get existing employee:

var (employee, err) = GetEmployeeById(3); if (err) { Console.WriteLine(err.ToString()); } else { Console.WriteLine(employee); }

Output:

Employee { FirstName = Emily, LastName = Johnson, Age = 28 }

Try to get non-existing employee:

var (employee, err) = GetEmployeeById(420); if (err) { Console.WriteLine(err.ToString()); }

Output:

NotFound: cannot find employee by id

We can get more details on the error:

var (employee, err) = GetEmployeeById(420); if (err) { var errDump = err.ToErrorDump(); var json = JsonSerializer.Serialize( errDump, new JsonSerializerOptions { WriteIndented = true } ); Console.WriteLine(json); }

Output:

{ "Kind": "NotFound", "Message": "cannot find employee by id", "ThreadContext": "ManagedThreadId=1, ApartmentState=MTA, Name=", "StackTrace": [ "at System.Environment.get_StackTrace()", "at RCi.ErrorAsValue.Error.New(Error inner, String kind, String message, ValueTuple`2[] args)", "at RCi.ErrorAsValue.Error.NewNotFound(String message, ValueTuple`2[] args)", "at TestUsage.Program.GetEmployeeById(Int32 id) in D:\\code\\src\\RCi.ErrorAsValue\\TestUsage\\Program.cs:line 52", "at TestUsage.Program.Test2() in D:\\code\\src\\RCi.ErrorAsValue\\TestUsage\\Program.cs:line 79", "at TestUsage.Program.Main() in D:\\code\\src\\RCi.ErrorAsValue\\TestUsage\\Program.cs:line 12" ], "Args": [ { "Name": "id", "Value": 420 } ] }