maybe.md

Maybe

Maybe is a structure for values that may not be present or for situations that may fail. A Maybe can help in dealing with optional values, arguments, records with optional fields, etc.

Implements: Alt, Monad, Semigroup, Setoid

• Maybe
  • Maybe.of(v)
  • Maybe.zero()
  • Maybe.Just(v)
  • Maybe.Nothing()
  • Maybe.fromNullable(v)
  • Maybe.withDefault(def, v)
  • Maybe.catMaybes(ar)
  • Maybe.isNothing(v)
  • Maybe.isJust(v)
  • Maybe.equals(n)
  • Maybe.map(f)
  • Maybe.chain(f)
  • Maybe.isNothing()
  • Maybe.isJust()
  • Maybe.alt(v)
  • Maybe.ap(j)
  • Maybe.getValue()

Maybe.of(v)

Creates a Just v.

Param	Type	Description
v	any	Value

Maybe.zero()

Creates a Nothing.

Maybe.Just(v)

Creates a Just v.

Param	Type	Description
v	any	Value

Maybe.Nothing()

Creates a Nothing.

Maybe.fromNullable(v)

Creates a Just if the value is not null or undefined; otherwise, creates a Nothing.

Param	Type	Description
v	any	Value

Maybe.withDefault(def, v)

Creates a Just if the value v is not null or undefined; otherwise, creates a Just with the default value def.

Param	Type	Description
def	any	Default value
v	any	Value

Maybe.catMaybes(ar)

A static method that takes an array of Maybe values and returns an array of the values of all the Just elements in the passed array.

Param	Type	Description
ar	Array.<any>	Array of Maybe values

Maybe.isNothing(v)

A static method that returns true if the passed Maybe is a Nothing.

Param	Type	Description
v	any	Maybe

Maybe.isJust(v)

A static method that returns true if the passed Maybe is a Just.

Param	Type	Description
v	any	Maybe

Maybe.equals(n)

Returns true if the current and the passed elements are of the Maybe type with the same value.

Param	Type	Description
n	any	Any value of type Setoid

Maybe.map(f)

Applies the passed function to the value of the current Maybe if it is a Just.

Param	Type	Description
f	function	Function

Maybe.chain(f)

Chains together many computations that return a Maybe type.

Param	Type	Description
f	function	Function that returns another Maybe

Maybe.isNothing()

Returns true if the current Maybe is a Nothing.

Maybe.isJust()

Returns true if the current Maybe is a Just.

Maybe.alt(v)

An instance method that returns the current Maybe if it is a Just; otherwise, returns the passed Maybe.

Param	Type	Description
v	any	Maybe

Maybe.ap(j)

Applies the function inside the passed Maybe to the current Maybe if it is a Just.

Param	Type	Description
j	any	Maybe with a function

Maybe.getValue()

Gets the value within the Maybe.