Simple Optional

A lightweight TypeScript implementation of an Optional container (inspired by Java's Optional). Encapsulates a value that may be present or absent, and provides helpers for safe access and transformations.

Features

• Create present, nullable, or empty optionals
• Check presence with isPresent() / isEmpty()
• Safe retrieval with get(), orElse(), and orElseThrow()
• Transform values with map()
• Conditional execution with ifPresent()

Usage

Import or include the class in your project, then:

• Create an Optional with a non-null value:

const o = Optional.of(42);

• Create an Optional that may be null:

const maybe = Optional.ofNullable<number>(null);

• Create an empty Optional:

const empty = Optional.empty<number>();

• Check presence:

if (o.isPresent()) { /* ... */ }
if (empty.isEmpty()) { /* ... */ }

• Execute when present:

o.ifPresent(v => console.log(v));

• Transform a value:

const str = Optional.of(5).map(n => 'Number ' + n); // Optional<string>

• Retrieve value with default or throw:

const x = maybe.orElse(10);
const y = maybe.orElseThrow(() => new Error('Missing value'));

Error handling

Errors are thrown as Error instances with class-prefixed messages, e.g. [Optional] No value present.

Notes & assumptions

• of() and set() treat both null and undefined as invalid.
• ofNullable() intentionally allows null to represent emptiness.
• The class uses a private constructor—use static factories to create instances.