Predicate Functions

All functions in this group have a signature of * -> Boolean and are used with the many predicate based functions that ship with crocks, like safe, ifElse and filter to name a few. They also fit naturally with the Pred ADT. All predicate functions can be referenced from crocks/predicates.

Below is a list of all the current predicates that are included with a description of their truth:

  • hasProp :: (String | Integer) -> a -> Boolean: an Array or Object that contains the provided index or key
  • hasProps :: Foldable f => f (String | Integer) -> a -> Boolean: an Array or Object that contains the provided indexs or keys
  • hasPropPath :: [ String | Integer ] -> a -> Boolean: an Array or Object that contains the provided index path
  • isAlt :: a -> Boolean: an ADT that provides map and alt methods
  • isAlternative :: a -> Boolean: an ADT that provides alt, zero, map, ap, chain and ofmethods
  • isApplicative :: a -> Boolean: an ADT that provides map, ap and of methods
  • isApply :: a -> Boolean: an ADT that provides map and ap methods
  • isArray :: a -> Boolean: Array
  • isBifunctor :: a -> Boolean: an ADT that provides map and bimap methods
  • isBoolean :: a -> Boolean: Boolean
  • isCategory :: a -> Boolean: an ADT that provides id and compose methods
  • isChain :: a -> Boolean: an ADT that provides map, ap and chain methods
  • isContravariant :: a -> Boolean: an ADT that provides contramap method
  • isDate :: a -> Boolean: Date
  • isDefined :: a -> Boolean: Every value that is not undefined, null included
  • isEmpty :: a -> Boolean: Empty Monoid, Object, Array, String, undefined, null, all Numbers and Boolean values
  • isExtend :: a -> Boolean: an ADT that provides map and extend methods
  • isFalse :: a -> Boolean: a value that is strictly equal to false
  • isFalsy :: a -> Boolean: a value that is considered to be falsy
  • isFoldable :: a -> Boolean: Array, List or any structure with a reduce method
  • isFunction :: a -> Boolean: Function
  • isFunctor :: a -> Boolean: an ADT that provides a map method
  • isInteger :: a -> Boolean: Integer
  • isIterable :: a -> Boolean: an Object with an iterator method
  • isMap :: a -> Boolean: Map
  • isMonad :: a -> Boolean: an ADT that provides map, ap, chain and of methods
  • isMonoid :: a -> Boolean: an ADT that provides concat and empty methods
  • isNil :: a -> Boolean: undefined or null or NaN
  • isNumber :: a -> Boolean: Number that is not a NaN value, Infinity included
  • isObject :: a -> Boolean: Plain Old JavaScript Object (POJO)
  • isPlus :: a -> Boolean: an ADT that provides map, alt and zero methods
  • isProfunctor :: a -> Boolean: an ADT that provides map, contramap and promap methods
  • isPromise :: a -> Boolean: an object implementing then and catch
  • isSame :: a -> b -> Boolean: same value or reference, use equals for value equality
  • isSameType :: a -> b -> Boolean: Constructor matches a values type, or two values types match
  • isSemigroup :: a -> Boolean: an ADT that provides a concat method
  • isSemigroupoid :: a -> Boolean: an ADT that provides a compose method
  • isSetoid :: a -> Boolean: an ADT that provides an equals method
  • isString :: a -> Boolean: String
  • isSymbol :: a -> Boolean: Symbol
  • isTraversable :: a -> Boolean: an ADT that provides map and traverse methods
  • isTrue :: a -> Boolean: a value that is strictly equal to true
  • isTruthy :: a -> Boolean: a value that is considered to be truthy
  • pathEq :: [ String | Integer ] -> a -> Object -> Boolean: an Object that contains the provided key in the traversal path, with a value equal to the provided value. (equality by value)
  • pathSatisfies :: [ String | Integer ] -> ((a -> Boolean) | Pred) -> Object -> Boolean: an Object that contains the provided key in the traversal path with a value that passes the provided predicate.
  • propEq :: (String | Integer) -> a -> Object -> Boolean: an Object that contains the provided key with a value equal to the provided value. (equality by value)
  • propSatisfies :: (String | Integer) -> ((a -> Boolean) | Pred) -> Object -> Boolean: an Object that contains the provided key with a value that passes the provided predicate.
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