lib-result/dist/index.js

A Rust-inspired `Result` type for type-safe error handling in TypeScript and JavaScript

// src/utils.ts
function toError(e) {
  if (e instanceof Error) return e;
  if (typeof e === "string") return new Error(e);
  if (isKeyValue(e)) return createCustomError(e);
  return new Error("Unknown error");
}
function isKeyValue(value) {
  return typeof value === "object" && value !== null && !Array.isArray(value);
}
function createCustomError(props) {
  const error = new Error(props?.message || "Unknown Error");
  if (isKeyValue(props)) {
    return Object.assign(error, props);
  }
  return error;
}

// src/mixens.ts
var methodsArray = [
  withIsOk,
  withIsError,
  withUnwrap,
  withExpect,
  withMap,
  withPipe,
  withMatch,
  withOrElse,
  withUnwrapOr
];
function compose(base, ...fns) {
  return Object.freeze(fns.reduce((obj, fn) => fn(obj), base));
}
function withIsOk(base) {
  return Object.assign(base, {
    isOk() {
      return this.error === void 0;
    }
  });
}
function withIsError(base) {
  return Object.assign(base, {
    isError() {
      return this.error !== void 0;
    }
  });
}
function withUnwrap(base) {
  return Object.assign(base, {
    unwrap() {
      if (this.isOk()) return this.ok;
      throw this.error;
    }
  });
}
function withExpect(base) {
  return Object.assign(base, {
    expect(message) {
      if (this.isOk()) return this.ok;
      throw createCustomError({
        message,
        cause: this.error
      });
    }
  });
}
function withMap(base) {
  return Object.assign(base, {
    map(fn) {
      try {
        if (this.isOk()) return Ok(fn(this.ok));
      } catch (e) {
        return Err(toError(e));
      }
      return Err(this.error);
    }
  });
}
function withPipe(base) {
  return Object.assign(base, {
    pipe(fn) {
      try {
        if (this.isOk()) return fn(this.ok);
      } catch (e) {
        return Err(toError(e));
      }
      return Err(this.error);
    }
  });
}
function withMatch(base) {
  return Object.assign(base, {
    match(okFn, errFn) {
      try {
        if (this.isOk()) return okFn(this.ok);
        return errFn(this.error);
      } catch (e) {
        return errFn(toError(e));
      }
    }
  });
}
function withOrElse(base) {
  return Object.assign(base, {
    orElse(errFn) {
      try {
        if (this.isOk()) return this.ok;
        return errFn(this.error);
      } catch (e) {
        throw toError(e);
      }
    }
  });
}
function withUnwrapOr(base) {
  return Object.assign(base, {
    unwrapOr(fallback) {
      return this.isOk() ? this.ok : fallback;
    }
  });
}
function Ok(ok) {
  return compose({ ok, error: void 0 }, ...methodsArray);
}
function Err(error) {
  if (!(error instanceof Error)) {
    throw new TypeError(
      "Err expects an Error instance, use ErrFromObject instead."
    );
  }
  return compose({ ok: void 0, error }, ...methodsArray);
}
function ErrFromText(message) {
  return compose(
    { ok: void 0, error: new Error(message) },
    ...methodsArray
  );
}
function ErrFromObject(props) {
  return compose(
    {
      ok: void 0,
      error: createCustomError(props)
    },
    ...methodsArray
  );
}

// src/main.ts
function wrap(callback) {
  try {
    return Ok(callback());
  } catch (error) {
    return Err(toError(error));
  }
}
async function wrapAsync(callback) {
  try {
    return Ok(await callback());
  } catch (error) {
    return Err(toError(error));
  }
}
function wrapThrowable(callback) {
  return (...args) => {
    try {
      return Ok(callback(...args));
    } catch (e) {
      return Err(toError(e));
    }
  };
}
function wrapAsyncThrowable(callback) {
  return async (...args) => {
    try {
      return Ok(await callback(...args));
    } catch (e) {
      return Err(toError(e));
    }
  };
}
export {
  Err,
  ErrFromObject,
  ErrFromText,
  Ok,
  wrap,
  wrapAsync,
  wrapAsyncThrowable,
  wrapThrowable
};