rescript-react-update

> useReducer with updates and side effects!

Installation

``console
$ yarn add rescript-react-update
`

or

`console
$ npm install --save rescript-react-update
`

Then add rescript-react-update to your bsconfig.json bs-dependencies field.

ReactUpdate.useReducer

`reason
type state = int;

type action =
| Increment
| Decrement;

[@react.component]
let make = () => {
let (state, send) =
ReactUpdate.useReducer((state, action) =>
switch (action) {
| Increment => Update(state + 1)
| Decrement => Update(state - 1)
},
0
);


;
};
`

$3

ReactUpdate.useReducerWithMapState

If you'd rather initialize state lazily (if there's some computation you don't want executed at every render for instance), use useReducerWithMapState where the first argument is a function taking unit and returning the initial state.

`reason
type state = int;

type action =
| Increment
| Decrement;

[@react.component]
let make = () => {
let (state, send) =
ReactUpdate.useReducerWithMapState(
(state, action) =>
switch (action) {
| Increment => Update(state + 1)
| Decrement => Update(state + 1)
},
() => 0
);


;
};
`

$3

The callback you pass to SideEffects & UpdateWithSideEffect returns an option(unit => unit), which is the cancellation function.

`reason
// doesn't cancel
SideEffects(({send}) => {
Js.log(1);
None
});
// cancels
SideEffects(({send}) => {
let request = Request.make();
request->Future.get(payload => send(Receive(payload)))
Some(() => {
Request.cancel(request)
})
});
`

If you want to copy/paste old reducers that don't support cancellation, you can use ReactUpdateLegacy instead in place of ReactUpdate. Its SideEffects and UpdateWithSideEffects functions accept functions that return unit`.