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Null
Provide utilities around null('a)
.
REStype t<'a> = Js.null<'a>
Local alias for Js.null('a)
.
RESlet return: 'a => t<'a>
Constructs a value of Js.null('a)
containing a value of 'a
.
test
RESlet test: t<'a> => bool
Returns true
if the given value is empty (null
), false
otherwise.
empty
RESlet empty: t<'a>
The empty value, null
.
getUnsafe
RESlet getUnsafe: t<'a> => 'a
getExn
RESlet getExn: t<'a> => 'a
bind
RESlet bind: (t<'a>, (. 'a) => 'b) => t<'b>
Maps the contained value using the given function.
If Js.null('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('b)
.
RESlet maybeGreetWorld = (maybeGreeting: Js.null<string>) =>
Js.Null.bind(maybeGreeting, (. greeting) => greeting ++ " world!")
iter
RESlet iter: (t<'a>, (. 'a) => unit) => unit
Iterates over the contained value with the given function.
If Js.null('a)
contains a value, that value is unwrapped and applied to the given function.
RESlet maybeSay = (maybeMessage: Js.null<string>) =>
Js.Null.iter(maybeMessage, (. message) => Js.log(message))
fromOption
RESlet fromOption: option<'a> => t<'a>
Maps option('a)
to Js.null('a)
.
Some(a)
=> a
None
=> empty
from_opt
RESlet from_opt: option<'a> => t<'a>
toOption
RESlet toOption: t<'a> => option<'a>
Maps Js.null('a)
to option('a)
.
a
=> Some(a)
empty
=> None
to_opt
RESlet to_opt: t<'a> => option<'a>