Option65

Constructors

fromIterableconstWraps the first element of an Iterable in a Some, or returns None if the iterable is empty.noneconstCreates an Option representing the absence of a value.someconstWraps the given value into an Option to represent its presence.

Models

NoneinterfaceRepresents the absence of a value within an Option.OptiontypeThe Option data type represents optional values.OptionUnifyinterfaceType-level unification support for Option values.OptionUnifyIgnoreinterfaceMarker interface used by Effect's Unify machinery for Option values.SomeinterfaceRepresents the presence of a value within an Option.

Guards

isNoneconstChecks whether an Option is None (absent).isOptionconstDetermines whether the given value is an Option.isSomeconstChecks whether an Option contains a value (Some).

Getters

getOrElseconstExtracts the value from a Some, or evaluates a fallback thunk on None.getOrNullconstExtracts the value from a Some, or returns null for None.getOrUndefinedconstExtracts the value from a Some, or returns undefined for None.

Elements

containsconstChecks whether an Option contains a value equal to the given one, using default structural equality.containsWithconstChecks whether an Option contains a value equivalent to the given one, using a custom Equivalence.existsconstChecks whether the value in a Some satisfies a predicate or refinement.

Mapping

asconstReplaces the value inside a Some with a constant, leaving None unchanged.asVoidconstReplaces the value inside a Some with void (undefined), leaving None unchanged.mapconstTransforms the value inside a Some using the provided function, leaving None unchanged.

Filtering

filterconstFilters an Option using a predicate.filterMapconstTransforms and filters an Option using a Filter callback.partitionMapconstSplits an Option into two Options using a function that returns a Result.

Sequencing

andThenconstChains a second computation onto an Option.composeKconstComposes two Option-returning functions into a single function that chains them together.flatMapconstApplies a function that returns an Option to the value of a Some, flattening the result.flatMapNullishOrconstCombines flatMap with fromNullishOr: applies a function that may return null/undefined to the value of a Some.flattenconstFlattens a nested Option<Option<A>> into Option<A>.tapconstRuns a side-effecting Option-returning function on the value of a Some, returning the original Option if the function returns Some, or None if it returns None.

Combiner

makeCombinerFailFastfunctionCreates a Combiner for Option<A> with fail-fast semantics: returns None if either operand is None.

Combining

allconstCombines a structure of Options (tuple, struct, or iterable) into a single Option containing the unwrapped structure.productconstCombines two Options into a Some containing a tuple [A, B] if both are Some.productManyconstCombines a primary Option with an iterable of Options into a tuple if all are Some.

Converting

fromNullishOrconstConverts a nullable value (null or undefined) into an Option.fromNullOrconstConverts a possibly null value into an Option, leaving undefined as a valid Some.fromUndefinedOrconstConverts a possibly undefined value into an Option, leaving null as a valid Some.getFailureconstConverts a Result into an Option, keeping only the failure value.getOrThrowconstExtracts the value from a Some, or throws a default Error for None.getOrThrowWithconstExtracts the value from a Some, or throws a custom error for None.getSuccessconstConverts a Result into an Option, keeping only the success value.liftNullishOrconstLifts a function that may return null or undefined into one that returns an Option.liftThrowableconstLifts a function that may throw into one that returns an Option.toArrayconstConverts an Option into an Array.toRefinementconstConverts an Option-returning function into a type guard (refinement).

Do Notation

bindconstAdds an Option value to the do notation record under a given name.bindToconstGives a name to the value of an Option, creating a single-key record inside Some.DoconstProvides an Option containing an empty record {}, used as the starting point for do notation chains.

Error Handling

firstSomeOfconstReturns the first Some found in an iterable of Options, or None if all are None.orElseconstReturns the fallback Option if self is None; otherwise returns self.orElseResultconstReturns the first available value and marks whether it came from the fallback.orElseSomeconstReturns Some of the fallback value if self is None; otherwise returns self.

Generators

genconstProvides generator-based syntax for Option, similar to async/await but for optional values.OptionIteratorinterfaceIterator protocol used to yield an Option inside gen, returning the contained value type back to the generator.

Instances

makeEquivalenceconstCreates an Equivalence for Option<A> from an Equivalence for A.

Lifting

lift2constLifts a binary function to operate on two Option values.liftPredicateconstLifts a Predicate or Refinement into the Option context: returns Some(value) when the predicate holds, None otherwise.

Pattern Matching

matchconstPattern-matches on an Option, handling both None and Some cases.

Reducer

makeReducerfunctionCreates a Reducer for Option<A> that prioritizes the first non-None value and combines values when both are Some.makeReducerFailFastfunctionCreates a Reducer for Option<A> by lifting an existing Reducer with fail-fast semantics.

Reducing

reduceCompactconstReduces an iterable of Options to a single value, skipping None entries.

Sorting

makeOrderconstCreates an Order for Option<A> from an Order for A.

Type Lambdas

OptionTypeLambdainterfaceType lambda interface for higher-kinded type encodings with Option.

Zipping

zipLeftconstSequences two Options, keeping the value from the first if both are Some.zipRightconstSequences two Options, keeping the value from the second if both are Some.zipWithconstCombines two Options using a provided function.