maybe.md
December 15, 2024 ยท View on GitHub
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.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.