🤼Either

Represents a value that can be either of type L (left) or R (right)

const either1: Either<string, number> = left("Error message");
const either2: Either<string, number> = right(42);

const result1 = fold(
    either1,
    (errorMessage) => `Error: ${errorMessage}`,
    (value) => `Success: ${value}`
); // "Error: Error message"

const result2 = fold(
    either2,
    (errorMessage) => `Error: ${errorMessage}`,
    (value) => `Success: ${value}`
); // "Success: 42"