/** * @license React * use-sync-external-store-shim/with-selector.development.js * * Copyright (c) Facebook, Inc. and its affiliates. * * This source code is licensed under the MIT license found in the * LICENSE file in the root directory of this source tree. */ 'use strict'; if (process.env.NODE_ENV !== "production") { (function() { 'use strict'; /* global __REACT_DEVTOOLS_GLOBAL_HOOK__ */ if ( typeof __REACT_DEVTOOLS_GLOBAL_HOOK__ !== 'undefined' && typeof __REACT_DEVTOOLS_GLOBAL_HOOK__.registerInternalModuleStart === 'function' ) { __REACT_DEVTOOLS_GLOBAL_HOOK__.registerInternalModuleStart(new Error()); } var React = require('react'); var shim = require('use-sync-external-store/shim'); /** * inlined Object.is polyfill to avoid requiring consumers ship their own * https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/is */ function is(x, y) { return x === y && (x !== 0 || 1 / x === 1 / y) || x !== x && y !== y // eslint-disable-line no-self-compare ; } var objectIs = typeof Object.is === 'function' ? Object.is : is; var useSyncExternalStore = shim.useSyncExternalStore; // for CommonJS interop. var useRef = React.useRef, useEffect = React.useEffect, useMemo = React.useMemo, useDebugValue = React.useDebugValue; // Same as useSyncExternalStore, but supports selector and isEqual arguments. function useSyncExternalStoreWithSelector(subscribe, getSnapshot, getServerSnapshot, selector, isEqual) { // Use this to track the rendered snapshot. var instRef = useRef(null); var inst; if (instRef.current === null) { inst = { hasValue: false, value: null }; instRef.current = inst; } else { inst = instRef.current; } var _useMemo = useMemo(function () { // Track the memoized state using closure variables that are local to this // memoized instance of a getSnapshot function. Intentionally not using a // useRef hook, because that state would be shared across all concurrent // copies of the hook/component. var hasMemo = false; var memoizedSnapshot; var memoizedSelection; var memoizedSelector = function (nextSnapshot) { if (!hasMemo) { // The first time the hook is called, there is no memoized result. hasMemo = true; memoizedSnapshot = nextSnapshot; var _nextSelection = selector(nextSnapshot); if (isEqual !== undefined) { // Even if the selector has changed, the currently rendered selection // may be equal to the new selection. We should attempt to reuse the // current value if possible, to preserve downstream memoizations. if (inst.hasValue) { var currentSelection = inst.value; if (isEqual(currentSelection, _nextSelection)) { memoizedSelection = currentSelection; return currentSelection; } } } memoizedSelection = _nextSelection; return _nextSelection; } // We may be able to reuse the previous invocation's result. // We may be able to reuse the previous invocation's result. var prevSnapshot = memoizedSnapshot; var prevSelection = memoizedSelection; if (objectIs(prevSnapshot, nextSnapshot)) { // The snapshot is the same as last time. Reuse the previous selection. return prevSelection; } // The snapshot has changed, so we need to compute a new selection. // The snapshot has changed, so we need to compute a new selection. var nextSelection = selector(nextSnapshot); // If a custom isEqual function is provided, use that to check if the data // has changed. If it hasn't, return the previous selection. That signals // to React that the selections are conceptually equal, and we can bail // out of rendering. // If a custom isEqual function is provided, use that to check if the data // has changed. If it hasn't, return the previous selection. That signals // to React that the selections are conceptually equal, and we can bail // out of rendering. if (isEqual !== undefined && isEqual(prevSelection, nextSelection)) { return prevSelection; } memoizedSnapshot = nextSnapshot; memoizedSelection = nextSelection; return nextSelection; }; // Assigning this to a constant so that Flow knows it can't change. // Assigning this to a constant so that Flow knows it can't change. var maybeGetServerSnapshot = getServerSnapshot === undefined ? null : getServerSnapshot; var getSnapshotWithSelector = function () { return memoizedSelector(getSnapshot()); }; var getServerSnapshotWithSelector = maybeGetServerSnapshot === null ? undefined : function () { return memoizedSelector(maybeGetServerSnapshot()); }; return [getSnapshotWithSelector, getServerSnapshotWithSelector]; }, [getSnapshot, getServerSnapshot, selector, isEqual]), getSelection = _useMemo[0], getServerSelection = _useMemo[1]; var value = useSyncExternalStore(subscribe, getSelection, getServerSelection); useEffect(function () { inst.hasValue = true; inst.value = value; }, [value]); useDebugValue(value); return value; } exports.useSyncExternalStoreWithSelector = useSyncExternalStoreWithSelector; /* global __REACT_DEVTOOLS_GLOBAL_HOOK__ */ if ( typeof __REACT_DEVTOOLS_GLOBAL_HOOK__ !== 'undefined' && typeof __REACT_DEVTOOLS_GLOBAL_HOOK__.registerInternalModuleStop === 'function' ) { __REACT_DEVTOOLS_GLOBAL_HOOK__.registerInternalModuleStop(new Error()); } })(); }