@jgierer12/hooks

My personal library of reusable React hooks

Installation

GitHub Package Registry

This package is published on both the GitHub Package Registry and the npm registry. To use the GPR, change the registry for the @jgierer12 scope before installing:

echo "@jgierer12:registry=https://npm.pkg.github.com" >> .npmrc

npm install @jgierer12/hooks

import { useMount } from "@jgierer12/hooks";
useMount(...)

// or

import * as hooks from "@jgierer12/hooks";
hooks.useMount(...)

API

Constants

useEventListener

Listen for a specified event and run a callback when it occurs

useMount

Run a callback only on initial mount, but not on rerenders

useObjectState

On setState, deep-merge old and new state objects. This resembles React.Component's this.setState, but with deep merging instead of shallow merging

usePersistentState

useState while persisting the state to localStorage across sessions

useRerender

Run a callback only on rerenders (if dependencies changed), but not on initial mount

useTimeout

Run a callback function after waiting for a specified duration

useEventListener

Listen for a specified event and run a callback when it occurs

Kind: global constant

Param	Type	Description
type	String	Type of the event to listen for
handler	function	Callback to run when the event occurs
target	EventTarget	DOM element to attach the listener to

Example

useEventListener(`click`, event => {
  console.log(`Clicked on ${event.target}`);
});

Example

useEventListener(
  `focus`,
  event => {
    console.log(`Input was focused`);
  },
  myInput
);

useMount

Run a callback only on initial mount, but not on rerenders

Kind: global constant

Param	Type	Description
effect	function	Effect callback to run

Example

useMount(() => {
  fetchExtraResources();
});

useObjectState

On setState, deep-merge old and new state objects. This resembles React.Component's this.setState, but with deep merging instead of shallow merging

Kind: global constant

Param	Type	Description
initialState	Object	Initial state

Example

const [state, setState] = useObjectState({
  name: {
    first: `Jonas`,
    middle: `Ben`,
    last: `Gierer`,
  },
  age: 4,
});

setState({
  name: {
    middle: ``,
  },
  age: 20,
});

console.log(state);
// {
//    name: {
//      first: `Jonas`,
//      middle: ``,
//      last: `Gierer`,
//    },
//    age: 20,
// }

usePersistentState

useState while persisting the state to localStorage across sessions

Kind: global constant

Param	Type	Description
key	String	The key under which the value should be stored
initialValue	*	Fallback initial value. Will be overwritten by value from localStorage if available

Example

const [name, setName] = usePersistentState(`name`, `Mike`);
setName(`Jonas`); // `name` will be initialized to `Jonas` instead of `Mike` in all future sessions

useRerender

Run a callback only on rerenders (if dependencies changed), but not on initial mount

Kind: global constant

Param	Type	Description
effect	function	Effect callback to run
deps	Array	Dependencies. Will be passed through to useEffect

Example

useRerender(() => {
  props.onChange(value);
}, [value]);

useTimeout

Run a callback function after waiting for a specified duration

Kind: global constant

Param	Type	Description
callback	function	Callback to run after the timeout
ms	Number	Time to wait in milliseconds
deps	Array	Dependencies. Will be passed through to useEffect
useEffect	function	Function to use instead of React.useEffect

Example

useTimeout(
  () => {
    console.log(`2 seconds have passed since the component was mounted`);
  },
  2000,
  null,
  useMount
);

Example

useTimeout(() => {
  console.log(
    `100 milliseconds have passed since the component was last rendered`
  );
}, 100);

Example

useTimeout(
  () => {
    console.log(`0.5 seconds have passed since myVar was last changed`);
  },
  500,
  [myVar],
  useRerender
);

License

MIT © 2019 Jonas Gierer