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API / Js / Null

You are currently looking at the v8.2 - v9.0 docs (Reason v3.6 syntax edition). You can find the latest API docs here.

Null

Provide utilities around null('a).

RES
type t<'a> = Js.null<'a>

Local alias for Js.null('a).

RES
let return: 'a => t<'a>

Constructs a value of Js.null('a) containing a value of 'a.

test

RES
let test: t<'a> => bool

Returns true if the given value is empty (null), false otherwise.

empty

RES
let empty: t<'a>

The empty value, null.

getUnsafe

RES
let getUnsafe: t<'a> => 'a

getExn

RES
let getExn: t<'a> => 'a

bind

RES
let 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).

RES
let maybeGreetWorld = (maybeGreeting: Js.null<string>) => Js.Null.bind(maybeGreeting, (. greeting) => greeting ++ " world!")

iter

RES
let 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.

RES
let maybeSay = (maybeMessage: Js.null<string>) => Js.Null.iter(maybeMessage, (. message) => Js.log(message))

fromOption

RES
let fromOption: option<'a> => t<'a>

Maps option('a) to Js.null('a). Some(a) => a None => empty

from_opt

RES
let from_opt: option<'a> => t<'a>

toOption

RES
let toOption: t<'a> => option<'a>

Maps Js.null('a) to option('a). a => Some(a) empty => None

to_opt

RES
let to_opt: t<'a> => option<'a>

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