README.md

React Hooks and utilities library

This library contains utilities and react hooks.

API hooks

import {} from '@anion155/react-hooks';

useConst

function useConst<T>(fabric: () => T): T;

Creates value on the first render, at render time.

const store = useConst(() => createStore());

useRenderEffect

type EffectCallback = () => (void | (() => void));
function useRenderEffect(effect: EffectCallback, deps: DependencyList): void;

Effect hook that runs at render time.

const ref = useRef(value);
useRenderEffect(() => {
  ref.current = value;
}, [value]);
// ref.current === value

Note

It is not guaranteed that cleanup function would be run during render. Specifically last cleanup before unmount is running as useEffect cleanup function.

useSetStateDispatcher

type SetStateDispatcher<T> = (state: T | ((current: T) => T)) => void;
function useSetStateDispatcher(get: () => T, set: (value: T) => void): SetStateDispatcher<T>;

Creates stable set state action dispatcher function, which accepts next value or modifier.

const store = {
  current: null,
  get() { return this.current; },
  set(next) { this.current = next },
};
const dispatcher = useSetStateDispatcher(
  () => store.get(),
  (next) => store.set(next),
);
dispatcher(10);
dispatcher(current => current * 2);

useEventState

function useEventState<T>(stateInitial: StateInitial<T>): [T, (arg: T) => void];
function useEventState<As extends unknown[], T>(
  stateInitial: StateInitial<T>,
  project: (...args: As) => T,
  deps: DependencyList
): [T, (...args: As) => void];

Creates event handler that stores event value in state.

const [value, handleChange] = useEventState('', (event) => event.target.value);
<>
  <input onChange={handleChange} />
  <span>Value: "{value}"</span>
</>

useStableCallback

function useStableCallback<F>(
  cb: (...args: Parameters<F>) => ReturnType<F>
): (...args: Parameters<F>) => ReturnType<F>;

Creates stable callback instance, result function never changes until unmounted.

const [counter, setCounter] = useState(1);
const cb = useStableCallback(() => {
  setCounter(counter + 1);
});
useEffect(() => {
  console.log('Runs one time only');
}, [cb]);
<button onClick={cb} />

useFabric

function useFabric<T>(fabric: () => T, deps: DependencyList): T;

Creates value every time deps are changed.

Note

This is fully controlled version of useMemo, that will not follow useMemo cache policies. See useMemo caveats

const controller = useFabric(() => new ControllerClass(value), [value]);

useInputState

function useInputState<T extends {}>(props: {
  value: T;
  defaultValue?: T;
  onValueChange: (value: T) => void;
}): [T, SetStateDispatcher<T>];
function useInputState<T extends {}>(props: {
  value?: T;
  defaultValue: T;
  onValueChange?: (value: T) => void;
}): [T, SetStateDispatcher<T>];

Creates tuple of value and set state acton dispatcher based on commonly used set of props value, onValueChange and defaultValue. Allows to create input components capable of being used as controlled component and as uncontrolled.

function CustomInput(props) {
  const [value, setValue] = useInputState(props);
  return <input value={value} onChange={e => setValue(e.value)} />
}
// uncontrolled version
<CustomInput defaultValue={5} />
// or as controlled input
const [value, setValue] = useState(5);
<CustomInput value={value} onValueChange={(e) => setValue(e.value)} />

useLensedState

function useLensedState<T, U>(
  sourceState: readonly [T, SetStateDispatcher<T>],
  getter: (state: T) => U,
  setter: (value: U, state: T) => T
): [U, SetStateDispatcher<U>];

Creates state tuple binded to source state.

const formState = useState({ name: '', password: '' });
<Context.Provider value={formState}> />
const [name, setName] = useLensedState(
  useContext(Context),
  form => form.name,
  (name, form) => ({ ...form, name })
);
setName(current => 'mr.' + current);

API utils

There is submodule with utility functions

import {} from '@anion155/react-hooks/utils';

hasOwnProperty

function hasOwnProperty<P extends string, T>(obj: unknown, propertyName: P): obj is { [p in P]: T };

Type safe check if object has own property.

if (hasOwnProperty(obj, 'field')) {
  obj.field; // ts now knows that obj has property 'field' of unknown type
}

cancelablePromise

class CanceledError extends Error;
type CancelablePromise<T> = Promise<T> & { cancel: () => void };
type CancelState = { canceled: boolean };
type CancelablePromiseExecutor<T> = (
  resolve: (value: T | PromiseLike<T>) => void,
  reject: (reason?: unknown) => void,
  state: Readonly<CancelState>
) => void | { (): void };
function cancelablePromise<T>(executor: CancelablePromiseExecutor<T>): CancelablePromise<T>;

Creates cancelable promise.

const promise = cancelablePromise((resolve, reject, state) => {
  const controller = new AbortController();
  fetch('/something', { signal: controller.signal });
  setTimeout(() => {
    if (!state.canceled) return;
    reject(new Error('Timeout'));
  }, 1000);
  return () => {
    controller.abort();
  };
});
promise.cancel();

asyncDelay

function asyncDelay(timeout: number): CancelablePromise<void>;

Creates cancelable promise that will be resolved with timeout passed.

await asyncDelay(1000);

compareProps

function compareProps(prev: DependencyList, next: DependencyList): boolean;

Compares two dependencies arrays, return true if they are equal.

compareProps(["same", 1], ["same", 2]) === 2;

useRenderDispatcher

function useRenderDispatcher<S>(
  deps: DependencyList,
  onChange: (state: S | undefined, prevDeps: DependencyList | undefined) => S
): S;

Creates cross render state based on deps.

const useMemo = (creator, deps) => useRenderDispatcher(deps, creator);