ok

Return success

When processing is successful

import { Result } from 'types-ddd';

return Result.ok<T, F>(/* ... resource type T */);

T: first generic type refer to the value to return in success case.

F: second one refer to the error type to return in failure case. By default is string

The resource accepts a generic type. It can be a primary type or a more dynamic type.

return Result.ok<string>("Hello World");

It do not throw error and return an object with attributes and result status

const result = Result.ok<string>("simple string");

console.log(result)

> Result {
    isSuccess: true, 
    isFailure: false, 
    error: null, 
    _value: "simple string",
    statusCodeNumber: 200,
    statusCode: "OK"
}

The returned value must be accessed by your key to get a result

const result = Result.ok<string>("simple string");

console.log(result.getResult())
> "simple string"

How to confirm that the return is really successful

const result = Result.ok<string>("simple string");

console.log(result.isSuccess);
> true

How to return an interface

class User {
    name: string;
}

const result = Result.ok<User>({name: "John"});

console.log(result.getResult())
> Object { name: "John" }

If you declared the return as an interface and returned a value other than the one defined. You will have an error

class User {
    name: string;
}

const result = Result.ok<User>("this is not user"); // Error

Result also accpet statusCode optionally, if you want to provide domain status for infra.

Result.ok<string>("Some success message", "OK");

// Available status success

	CONTINUE = 100,
	SWITCHING_PROTOCOL = 101,
	PROCESSING = 102,
	OK = 200,
	CREATED = 201,
	ACCEPTED = 202,
	NON_AUTHORITATIVE = 203,
	NO_CONTENT = 204,
	RESET_CONTENT = 205,
	PARTIAL_CONTENT = 206,

	

By default

success result has status "OK" = 200

failure result has "UNPROCESSABLE_ENTITY" = 422

You also can return a void using Result.success instead Result.ok. Let's see a real use case

const saveUser = async (user:User):Promise<Result<void>> => {
    try{
      await connection.save(user);
      
      // for void use Result.success
      return Result.success<void>(); 
    }
    catch(error){
      return Result.fail<void>(error.message, "INTERNAL_SERVER_ERROR");
    }
}


// get result
const result => await saveUser(user);

console.log(result.isSuccess);
> true

It is possible to define an internationalization error message

interface IUser {
    name: string;
}

interface IErrorMessage {
    PT_BR: string;
    EN_US: string;
}

const createUser = (name: string): Result<IUser, IErrorMessage> => {
   if (name.length > 20 && name.length < 3) {
       return Result.fail({ PT_BR: "Nome inválido", EN_US: "Invalid name" })
   }
   else {
       return Result.ok({ name });
   }
}

const userOrError = createUser("Valid name");

console.log(userOrError.isSuccess);
> true

const newUserOrError = createUser("");
console.log(newUserOrError.error.EN_US);
> "Invalid name"