connect react components with wire
- top-level components
- doesn't care about the value
- care about the connection between components
- detailed components
- only care about the value
- doesn't care about where the value came from or will be used
- controlled/uncontrolled components should be easy to write
- choosing the correct state location shouldn't be too hard
yarn add @forminator/react-wireAdd proxy-polyfill to support ie browser. proxy support is more than 90% in browsers, more detail
With pure react, you use useState to store state:
function FancyInput(props) {
const [value, setValue] = useState('');
return <input value={value} onChange={(e) => setValue(e.target.value)} />;
}function FancyPage() {
return <FancyInput />;
}Let's add a new feature, a filterable list that gets a string as a filter and only shows items containing that string. Now we need to read the state of input outside of the FancyInput component; so we have to move the state to the parent component:
function FancyInput(props) {
- const [value, setValue] = useState('');
+ const { value, setValue } = props;
return <input value={value} onChange={(e) => setValue(e.target.value)} />;
}function FancyList(props) {
const [filter, setFilter] = useState('');
return (
<>
<FancyInput value={filter} setValue={setFilter} />
<List items={props.items} filter={filter} />
</>
);
}- you need to refactor all the
FancyInputusages, passvalue, andsetValueto make it work as expected - the top-level component (
FancyList) re-renders each time thefilterchanges
Let see how react-wire helps you:
Same as above, but use useWireState instead of useState:
function FancyInput(props) {
const [value, setValue] = useWireState(null, '');
return <input value={value} onChange={(e) => setValue(e.target.value)} />;
}Right now FancyInput is uncontrolled. If you need to make it controllable, you should pass an up-link wire.
function FancyInput(props) {
- const [value, setValue] = useWireState(null, '');
+ const [value, setValue] = useWireState(props.value$, '');
return <input value={value} onChange={(e) => setValue(e.target.value)} />;
}And create a wire with the useWire hook and pass it to components:
function FancyList(props) {
const filter$ = useWire(null, '');
return (
<>
<FancyInput value$={filter$} />
<List items={props.items} filter$={filter$} />
</>
);
}With this new code:
- all the
FancyInputuncontrolled usages are working as expected without any change - the Top-level component (
FancyList) will not re-render each time the value changes - only detailed components (
FancyInput,List) will re-render each time the value changes FancyInputis now controllable and can be used as a controlled or uncontrolled component by passing a wireFancyListcan be controllable if you want:
function FancyList(props) {
const filter$ = useWire(props.filter$, '');
/* ... */
}react-wire has more advanced features:
- selectors to maintain calculated values
- fns to pass function calls over the wire
useWire hook creates and returns new wire. in the next renders, returns the same wire.
// without up-link wire and initial value
const wire = useWire<type>(null);// with initial value
const wire = useWire(null, initialValue);// with up-link wire
const wire = useWire(anotherWire);// with up-link and initial value
const wire = useWire(anotherWire, initialValue);- If up-link wire has value, initial value will be ignored
- If up-link wire has
undefinedvalue, initial value will be set on up-link wire
// Lazy initial value
const wire = useWire(anotherWire, () => initialValue);useWireValue hook returns current wire value and subscribes for value updates
const value = useWireValue(wire);// returns `defaultValue` if the wire is `null` or `undefined` or wire has an `undefined` value
const value = useWireValue(wire, defaultValue);useWireState behaves like react useState, and keeps state and wire value in sync
// exactly same as useState
const [state, setState] = useWireState(null, initialValue);// without initial value
const [state, setState] = useWireState(wire);// with wire and initial value
const [state, setState] = useWireState(wire, initialValue);- If the wire has value, the initial value will be ignored and respect wire value
- If the wire has
undefinedvalue, the initial value will be used and wire value will be updated
// Lazy initial value
const [state, setState] = useWireState(wire, () => initialValue);// new value
setState(value);// functional update
setState((value) => update(value));note: If current state is undefined, updater function won't be called! you can pass initialValue to useWireState or make sure the wire has value to avoid this behavior.
// get value
const value = wire.getValue();// set value
wire.setValue(someValue);With fns object and useFn hook, you can transfer function calls over wires. Callback function should be memoized with useCallback
// subscribe for `sample` function call
useFn(
wire,
'sample',
useCallback((value) => {
console.log(value);
}, []),
);
// call `sample` function
wire.fns.sample(5);you can define typing for fns and useFn.
type Value = number;
interface Fns {
sample: (n: number) => void;
}
const wire = useWire<Value, Fns>(null);// code
wire.fns.sample();error:
error TS2554: Expected 1 arguments, but got 0.
wire.fns.sample();
~~~~~~~~
sample: (n: number) => void;
~~~~~~~~~
An argument for 'n' was not provided.
// code
useFn(
wire,
'sample',
useCallback((n: string) => {}, []),
);error:
error TS2345: Argument of type '(n: string) => void' is not assignable to parameter of type '(n: number) => void'.
Types of parameters 'n' and 'n' are incompatible.
Type 'number' is not assignable to type 'string'.
useFn(wire, 'sample', useCallback((n: string) => {}, []));
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
up-link wire should have an exact type for each function, but can have more functions.
interface AB {
a: (n: number) => void;
b: (n: string) => void;
}
interface A {
a: (n: number) => void;
}
interface B {
b: (n: string) => void;
}
interface C {
c: (n: string) => void;
}
const wireAB = useWire<Value, AB>(null);
const wireA = useWire<Value, A>(wireAB);
const wireB = useWire<Value, B>(wireAB);
const wireB = useWire<Value, C>(wireAB); // errorIf you want have a global wire you can createWire function.
const themeWire = createWire<'light' | 'dark'>('light');
function SomeComponent() {
const theme = useWireValue(themeWire);
}useSelector creates and returns a new selector. a selector is a wire with the calculated value.
const wire = useWire(null, 4);
const selector = useSelector({
get: ({ get }) => get(wire) * 2,
});
selector.getValue(); // 8You can create a writable selector with passing the set option.
const wire = useWire(null, 4);
const selector = useSelector({
get: ({ get }) => get(wire) * 2,
set: ({ set }, value) => set(wire, value / 2),
});
selector.setValue(6);
wire.getValue(); // 3You can define a dependencies list for dependencies of options.
const { n } = props;
const wire = useWire(null, 4);
const selector = useSelector(
{
get: ({ get }) => get(wire) * n,
set: ({ set }, value) => set(wire, value / n),
},
[n],
);createSelector creates a new selector. It can be used outside of the react.
const themeWire = createWire<'light' | 'dark'>('light');
const textColor = createSelector({
get: ({ get }) => (get(themeWire) === 'light' ? '#000' : '#fff'),
});
function SomeComponent() {
const color = useWireValue(textColor);
}Every time the wire value changes, the callback function would be called
// subscribe
useSubscribe(
wire,
useCallback((value) => {
/* ... */
}, []),
);Every time the wire value changes, the callback function would be called
more detail
// subscribe
const unsubscribe = wire.subscribe((value) => {
/* ... */
});
// unsubscribe
unsubscribe();in some rare use-cases you need changing wire behavior and interfering set value. useInterceptor helps in these use-cases.
more detail
useInterceptor hook gets wire and interceptor function and returns new wire. on every setValue of returned wire, the interceptor function gets next value and previous value and returns a new value. the returned value of the interceptor will be set on the wire.
const wire = useInterceptor(anotherWire, (nextValue, preValue) => /* anotherValue */)example:
const valueWire = useInterceptor(
props.valueWire,
useCallback(
(nextValue, preValue) =>
props.submittingWire.getValue() ? preValue : nextValue,
[props.submittingWire],
),
);undefinedvalue means the wire has no value and other wires may set its value during their initialization.nullvalue means the wire has value and value isnulland other wires don't override its value during their initialization
During initialization, wire value always has more priority.
- If the up-link wire has value, the initial value will be ignored and respect up-link wire value
- In CSR, If the up-link wire has
undefinedvalue, the initial value will be used and up-link wire value will be updated - In SSR, If the up-link wire has
undefinedvalue, the initial value will be used and a warning will be shown
Examples:
const wire1 = useWire(null, 1);
const wire2 = useWire(wire1, 2);
wire1.getValue(); // => 1
wire2.getValue(); // => 1const wire1 = useWire(null);
const wire2 = useWire(wire1, 2);
wire1.getValue(); // => 2
wire2.getValue(); // => 2const wire = useWire(null, 1);
const [state] = useWireState(wire, 2);
wire.getValue(); // => 1
state; // => 1const wire = useWire(null);
const [state] = useWireState(wire, 2);
wire.getValue(); // => 2
state; // => 2// ssr
const wire1 = useWire(null);
const wire2 = useWire(wire1, 2); // warning: 'upLink value is undefined. uplink without value is not supported in server side rendering'
wire1.getValue(); // => undefined
wire2.getValue(); // => 2// ssr
const wire1 = useWire(null);
const wire2 = useWire(wire1);
wire1.getValue(); // => undefined
wire2.getValue(); // => undefinedIn SSR, up-link wire without value is not supported. if you use up-link wire without value, a warning will be shown.
Please avoid changing the wire variable. if wire argument changed, a warning will be shown.
// wrong, avoid.
const wire = useWire(condition ? wire1 : wire2);
const value = useWireValue(condition ? wire1 : wire2);
const [state, setState] = useWireState(condition ? wire1 : wire2);