snippet for a blog post

result-util.ts

export class ResultT<E, T> {
  private result: Result<ErrorClassification, T>;

  constructor(result: Result<ErrorClassification, T>) {
    this.result = result;
  }

  ok(onSuccessFn: (lifted: T) => ResultT<E, T>): ResultT<E, T> {
    return isError(this.result) ? this : onSuccessFn(this.result as T);
  }

  err(onFailureFn: (error: ErrorClassification) => ResultT<E, T>): ResultT<E, T> {
    return isError(this.result) ? onFailureFn(this.result as ErrorClassification) : this;
  }

  map<A>(transformFn: (a: T) => A): ResultT<never, T> {
    this.result = transformFn(this.result as T) as any;
    return this;
  }
}