Result Patter with Typescript. Inspired By result.dart of the flutter architecture guide.

result.ts

class Success<T> {
  readonly isOk = true;
  readonly isFailure = false;
  value: T;

  constructor(value: T) {
    this.value = value;
  }
}

class Failure<E> {
  readonly isOk = false;
  readonly isFailure = true;
  error: E;

  constructor(error: E) {
    this.error = error;
  }
}
export type Result<T, E> = Success<T> | Failure<E>;
export const failure = <E>(e: E): Failure<E> => new Failure(e);
export const success = <T>(t: T): Success<T> => new Success(t);

/*
// Code example:
const apiGet = (): Result<string, Error> => {
  try {
    const response = 'response';
    return success(response);
  } catch (error) {
    return failure(new Error('Error getting data'));
  }
}
const result = apiGet();
if(result.isOk()) {
  console.log(result.value);
} else {
  console.log(result.error);
} 
*/