A pragmatic functional programming library for JavaScript/TypeScript

Box: computation with one value

Pair: computation with two values

List: computation with zero, one or more values

NonEmptyList: computation with one or more values

Option: computation with a value that may be present or absent

Result: synchronous computation that may succeed or fail, short-circuits when a failure occurs

Validated: like Result, but accumulates errors instead of short-circuiting

State: stateful computation

Writer: computation with additional data (used for logging)

StringWriter: computation with log entries concatenated to a string

ListWriter: computation with log entries concatenated to a List instance

Future: asynchronous computation that may succeed or fail (a monadic alternative to Promises)

Program: interpretation of program descriptions

Action: wrapper around a function with no parameters that enables composition

Arrow: wrapper around a function with one or more parameters that enables composition and adaptation of the input

Semigroup: a type that supports an associative binary operation

objectCombination: a function to create combination schemes for objects based on semigroups

Monoid: a semigroup with an identity element

All: combines two booleans using logical AND

Any: combines two booleans using logical OR

Min: combines two numbers, resulting in the smallest of the two

Max: combines two numbers, resulting in the largest of the two

Sum: combines two numbers, resulting in the sum of the two

Product: combines two numbers, resulting in the product of the two

Earliest: combines two dates, resulting in the earlier of the two

Latest: combines two dates, resulting in the later of the two

StringConcatenation: combines two string using concatenation

ArrayConcatenation: combines two arrays using concatenation

ListConcatenation: combines two lists using concatenation

Equivalence: testing of equivalence between two values of the same type

objectEquivalence: a function to create equivalence schemes for objects based on member equivalences

Equalities for basic types: equalities for string, number, boolean and Date values and arrays of such values

Order: decision on the order of two values

Ordering: a type alias for the three possible outcomes (-1, 0 and 1)

Predicate: wrapper around predicate functions