use-sync-external-store
Version:
Backwards compatible shim for React's useSyncExternalStore. Works with any React that supports hooks.
86 lines (84 loc) • 2.69 kB
JavaScript
/**
* @license React
* use-sync-external-store-shim/with-selector.production.js
*
* Copyright (c) Meta Platforms, Inc. and affiliates.
*
* This source code is licensed under the MIT license found in the
* LICENSE file in the root directory of this source tree.
*/
;
var React = require("react"),
shim = require("use-sync-external-store/shim");
function is(x, y) {
return (x === y && (0 !== x || 1 / x === 1 / y)) || (x !== x && y !== y);
}
var objectIs = "function" === typeof Object.is ? Object.is : is,
useSyncExternalStore = shim.useSyncExternalStore,
useRef = React.useRef,
useEffect = React.useEffect,
useMemo = React.useMemo,
useDebugValue = React.useDebugValue;
exports.useSyncExternalStoreWithSelector = function (
subscribe,
getSnapshot,
getServerSnapshot,
selector,
isEqual
) {
var instRef = useRef(null);
if (null === instRef.current) {
var inst = { hasValue: !1, value: null };
instRef.current = inst;
} else inst = instRef.current;
instRef = useMemo(
function () {
function memoizedSelector(nextSnapshot) {
if (!hasMemo) {
hasMemo = !0;
memoizedSnapshot = nextSnapshot;
nextSnapshot = selector(nextSnapshot);
if (void 0 !== isEqual && inst.hasValue) {
var currentSelection = inst.value;
if (isEqual(currentSelection, nextSnapshot))
return (memoizedSelection = currentSelection);
}
return (memoizedSelection = nextSnapshot);
}
currentSelection = memoizedSelection;
if (objectIs(memoizedSnapshot, nextSnapshot)) return currentSelection;
var nextSelection = selector(nextSnapshot);
if (void 0 !== isEqual && isEqual(currentSelection, nextSelection))
return (memoizedSnapshot = nextSnapshot), currentSelection;
memoizedSnapshot = nextSnapshot;
return (memoizedSelection = nextSelection);
}
var hasMemo = !1,
memoizedSnapshot,
memoizedSelection,
maybeGetServerSnapshot =
void 0 === getServerSnapshot ? null : getServerSnapshot;
return [
function () {
return memoizedSelector(getSnapshot());
},
null === maybeGetServerSnapshot
? void 0
: function () {
return memoizedSelector(maybeGetServerSnapshot());
}
];
},
[getSnapshot, getServerSnapshot, selector, isEqual]
);
var value = useSyncExternalStore(subscribe, instRef[0], instRef[1]);
useEffect(
function () {
inst.hasValue = !0;
inst.value = value;
},
[value]
);
useDebugValue(value);
return value;
};