@okeeffed/eitherify

Eitherify

A small utility to lift/lower a type to an Either category.

It does this by taking in a more idiomatic JavaScript function and create a partially-applied higher-order function.

The higher-order function will return any data returned from the original function as a Success<T> type where T is the data-type from the originally returned function.

Example

Given the following function:

function _toUpperCase(str: string) {
  return str.toUpperCase();
}

You can apply the higher-order function like so:

const toUpperCase = eitherify(_toUpperCase);

Now the return type of toUpperCase with be Either<string>.

If the function succeeds, the object will look like the following:

const result = toUpperCase("string");

console.log(result);

// If success, result will look like so:
result = {
  success: true,
  data: "STRING",
};

// If an error was thrown, result will look like so:
result = {
  success: false,
  error: thrownError, // value of whatever is thrown
};

Caveats

• Only supports an arity of one for any given function.