Null_undefined
Contains functionality for dealing with values that can be both null
and undefined
t
type t<'a> = Js.nullable<'a> = Value('a) | Null | Undefined
Local alias for Js.null_undefined<'a>
.
return
let return: 'a => t<'a>
Constructs a value of Js.null_undefined<'a>
containing a value of 'a
.
isNullable
let isNullable: t<'a> => bool
Returns true
if the given value is null or undefined, false
otherwise.
null
let null: t<'a>
The null value of type Js.null_undefined<'a>
.
undefined
let undefined: t<'a>
The undefined value of type Js.null_undefined<'a>
.
bind
let bind: (t<'a>, 'a => 'b) => t<'b>
Maps the contained value using the given function.
If Js.null_undefined<'a>
contains a value, that value is unwrapped, mapped to
a 'b
using the given function a' => 'b
, then wrapped back up and returned
as Js.null_undefined<'b>
.
Examples
RESCRIPTlet maybeGreetWorld = (maybeGreeting: Js.null_undefined<string>) =>
Js.Null_undefined.bind(maybeGreeting, (. greeting) => greeting ++ " world!")
iter
let iter: (t<'a>, 'a => unit) => unit
Iterates over the contained value with the given function.
If Js.null_undefined<'a>
contains a value, that value is unwrapped and applied to the given function.
Examples
RESCRIPTlet maybeSay = (maybeMessage: Js.null_undefined<string>) =>
Js.Null_undefined.iter(maybeMessage, (. message) => Js.log(message))
fromOption
let fromOption: option<'a> => t<'a>
Maps option<'a>
to Js.null_undefined<'a>
.
Some(a)
=> a
None
=> undefined
from_opt
Deprecated
Use fromOption instead
let from_opt: option<'a> => t<'a>
toOption
let toOption: t<'a> => option<'a>
Maps Js.null_undefined<'a>
to option<'a>
.
a
=> Some(a)
undefined
=> None
null
=> None
to_opt
Deprecated
Use toOption instead
let to_opt: t<'a> => option<'a>