Optional type is a type that represents either a value or the absence of a value.
Optional types make absence explicit. Instead of allowing any value to be null, the type itself says that a value might not exist.
Examples include:
Option<T>in RustMaybe ain HaskellOptional<T>in JavaT | undefinedorT | nullin TypeScript
Optional types are useful for:
- Return values that may not exist
- Avoiding unchecked null values
- Making missing data visible in function signatures
An optional value usually has to be checked, matched, or unwrapped before the contained value can be used.
Anki
id: optional-type-definition deck: Computer Science::Data Types tags: data-types optional-type
Q: What is an optional type? A: An optional type represents either a value or the absence of a value.
id: optional-type-purpose deck: Computer Science::Data Types tags: data-types optional-type null
Q: Why are optional types useful? A: Optional types make absence explicit in the type system and can reduce unchecked null-related errors.