UNPKG

@react-hookz/web

Version:

React hooks done right, for browser and SSR.

58 lines (57 loc) 1.9 kB
import { useEffect } from 'react'; import { useSafeState } from '..'; var queriesMap = new Map(); var querySubscribe = function (query, setState) { var entry = queriesMap.get(query); if (!entry) { var mql_1 = matchMedia(query); var dispatchers_1 = new Set(); var listener = function () { dispatchers_1.forEach(function (d) { return d(mql_1.matches); }); }; if (mql_1.addEventListener) mql_1.addEventListener('change', listener, { passive: true }); else mql_1.addListener(listener); entry = { mql: mql_1, dispatchers: dispatchers_1, listener: listener, }; queriesMap.set(query, entry); } entry.dispatchers.add(setState); setState(entry.mql.matches); }; var queryUnsubscribe = function (query, setState) { var entry = queriesMap.get(query); // else path is impossible to test in normal situation /* istanbul ignore else */ if (entry) { var mql = entry.mql, dispatchers = entry.dispatchers, listener = entry.listener; dispatchers.delete(setState); if (!dispatchers.size) { queriesMap.delete(query); if (mql.removeEventListener) mql.removeEventListener('change', listener); else mql.removeListener(listener); } } }; /** * Tracks the state of CSS media query. * * Return undefined initially and later receives correct value. * * @param query CSS media query to track. */ export function useMediaQuery(query) { var _a = useSafeState(), state = _a[0], setState = _a[1]; useEffect(function () { querySubscribe(query, setState); return function () { return queryUnsubscribe(query, setState); }; // eslint-disable-next-line react-hooks/exhaustive-deps }, [query]); return state; }