use-single-state v1.0.1

useSingleState

A React hook for using a unified state, with optional state diff logging

Using a single state object with React hooks allows you to update multiple state values in one call in functional components, similar to how setState updates state in class components.

We can also reset the state to its initial value, replace it altogether, and log state diffs to the console.

Installation

npm install use-single-state

or

yarn add use-single-state

Basic usage

import useSingleState from 'use-single-state';

const [{ text, value, note }, update] = useSingleState({
	text: '',
	value: 0,
	note: ''
});

update({
	note: 'New note'
});

Resetting state

• You can reset the whole state back to its initial value with the reset function.

const [{ text, value }, update, reset] = useSingleState(
	{
		text: '',
		value: 0
	},
	'My component'
);

update({
	text: 'New text',
	value: 5
});

// State is now { text: 'New text', value: 5 }

reset();

// State is now { text: '', value: 0 }

Diff logging

• useSingleState can optionally log diffs to your state to your console. The format of the diff output is modelled after redux-logger.
• This is turned off by default. To enable this, set a label for your hook with the label parameter. You can override this with the last parameter enableLog, which defaults to true.

Example code:

const [{ text, value }, update] = useSingleState(
	{
		text: '',
		value: 0
	},
	'My component'
);

update({
	text: 'New text'
});

Replacing state

• You can set the entire state with the replace function. Unlike update, the state is replaced and not merged.

const [{ text, value }, update, reset, replace] = useSingleState(
	{
		text: '',
		value: 0
	},
	'My component'
);

replace({
	text: 'New text'
});

// State is now { text: 'New text' }. 'value' has been discarded.

Comparison to useState and useReducer

• useSingleState will often be less verbose than having multiple uses of useState.
• useSingleState will only ever result in a single state update being sent to React's batcher when you need to update multiple state values at a time, likely saving your component from unnecessary re-renders.

// With useState
const [text, setText] = useState('');
const [value, setValue] = useState(0);
const [note, setNote] = useState('');

setNote('New note');
setText('Updated text');
setValue(9);

// With useSingleState
const [{ text, value, note }, update] = useSingleState({
	text: '',
	value: 0,
	note: ''
});

update({
	note: 'New note',
	text: 'Updated text',
	value: 9
});

• useSingleState works well in situations where your component isn't complex enough to warrant managing your state with useReducer, but you still want to update multiple state values at once.

/// With useReducer
const reducer = (state, action) => {
	switch (action.type) {
		case 'fail':
			return {
				loading: false,
				error: action.error,
				data: null
			};
		case 'loading': {
			return {
				loading: true,
				error: null,
				data: null
			};
		}
		case 'success': {
			return {
				loading: false,
				error: null,
				data: action.data
			};
		}
		default:
			throw new Error();
	}
};

const [{ data, loading, error }, dispatch] = useReducer(reducer, {
	loading: false,
	data: null,
	error: null
});

dispatch({
	type: 'loading'
});

dispatch({
	type: 'success',
	data
});

// With useSingleState
const [{ loading, data, error }, update] = useSingleState({
	loading: false,
	data: null,
	error: null
});

update({
	loading: true
});

update({
	loading: false,
	data
});