Function ok

Create an instance of Ok.

If you need to create an instance with a specific type (as you do whenever you are not constructing immediately for a function return or as an argument to a function), you can use a type parameter:

const yayNumber = Result.ok<number, string>(12);
Copy

Note: passing nothing, or passing null or undefined explicitly, will produce a Result<Unit, E>, rather than producing the nonsensical and in practice quite annoying Result<null, string> etc. See Unit for more.

const normalResult = Result.ok<number, string>(42);
const explicitUnit = Result.ok<Unit, string>(Unit);
const implicitUnit = Result.ok<Unit, string>();
Copy

In the context of an immediate function return, or an arrow function with a single expression value, you do not have to specify the types, so this can be quite convenient.

type SomeData = {
  //...
};

const isValid = (data: SomeData): boolean => {
  // true or false...
}

const arrowValidate = (data: SomeData): Result<Unit, string> =>
  isValid(data) ? Result.ok() : Result.err('something was wrong!');

function fnValidate(data: someData): Result<Unit, string> {
  return isValid(data) ? Result.ok() : Result.err('something was wrong');
}
Copy

Typeparam

T The type of the item contained in the Result.

Create an instance of Ok.

If you need to create an instance with a specific type (as you do whenever you are not constructing immediately for a function return or as an argument to a function), you can use a type parameter:

const yayNumber = Result.ok<number, string>(12);
Copy

Note: passing nothing, or passing null or undefined explicitly, will produce a Result<Unit, E>, rather than producing the nonsensical and in practice quite annoying Result<null, string> etc. See Unit for more.

const normalResult = Result.ok<number, string>(42);
const explicitUnit = Result.ok<Unit, string>(Unit);
const implicitUnit = Result.ok<Unit, string>();
Copy

In the context of an immediate function return, or an arrow function with a single expression value, you do not have to specify the types, so this can be quite convenient.

type SomeData = {
  //...
};

const isValid = (data: SomeData): boolean => {
  // true or false...
}

const arrowValidate = (data: SomeData): Result<Unit, string> =>
  isValid(data) ? Result.ok() : Result.err('something was wrong!');

function fnValidate(data: someData): Result<Unit, string> {
  return isValid(data) ? Result.ok() : Result.err('something was wrong');
}
Copy

Typeparam

T The type of the item contained in the Result.