Nothing
Nothing is a Maybe constructor representing the absence of a contained value or additional failure information.
Functional Programming in JavaScript
A Maybe case that represents the absence of a value or a failure without extra detail.
- How it is used
- Represents missing results in Maybe-based lookup and chaining flows.
- How deep it goes
- Defines the empty Maybe case and shows how it preserves map chains and fallback handling, but not custom Nothing internals.
- Examples
- Uses safe student lookup, chained property access, and the error 'Can't extract the value of a Nothing.'
- What you can do after
- Apply Maybe to keep missing data explicit while chaining operations and supplying defaults.
Read how Functional Programming in JavaScript explains Nothing →
Learn Haskell by Example
Nothing is the Maybe constructor representing the absence of a contained value.
- How it is used
- Represents missing or optional results while keeping failure explicit and non-crashing.
- How deep it goes
- Defines the constructor and demonstrates pattern matching, defaults, and associative-list updates without covering deeper Maybe abstractions.
- Examples
- Uses argument parsing, fromMaybe defaults, and an alter function where Nothing removes or signifies a missing mapping.
- What you can do after
- Apply Nothing through pattern matching to represent absence, choose defaults, and control pure updates.
Related concepts
- maybe functionpart of · The maybe function eliminates a Maybe value by returning a default for Nothing or applying a handler to the contained value.
- readMaybeproduced by · readMaybe is a Haskell function that parses a String into a value of a Read instance and returns Nothing when parsing fails.
- optionuses · An option type is a type that explicitly represents either a value of a specified type or the absence of a value.
- Justalternative to · Just is a constructor of the Maybe type that represents a present value by wrapping it.
- monadpart of · A monad is a functional abstraction that encapsulates computational context and provides operations for composing computations while preserving that context.
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