Gazebo_simulation-Frontend/node_modules/react-redux/lib/hooks/useSelector.js
2020-12-21 10:29:31 -05:00

146 lines
4.7 KiB
JavaScript

"use strict";
var _interopRequireDefault = require("@babel/runtime/helpers/interopRequireDefault");
exports.__esModule = true;
exports.createSelectorHook = createSelectorHook;
exports.useSelector = void 0;
var _react = require("react");
var _invariant = _interopRequireDefault(require("invariant"));
var _useReduxContext2 = require("./useReduxContext");
var _Subscription = _interopRequireDefault(require("../utils/Subscription"));
var _useIsomorphicLayoutEffect = require("../utils/useIsomorphicLayoutEffect");
var _Context = require("../components/Context");
var refEquality = function refEquality(a, b) {
return a === b;
};
function useSelectorWithStoreAndSubscription(selector, equalityFn, store, contextSub) {
var _useReducer = (0, _react.useReducer)(function (s) {
return s + 1;
}, 0),
forceRender = _useReducer[1];
var subscription = (0, _react.useMemo)(function () {
return new _Subscription["default"](store, contextSub);
}, [store, contextSub]);
var latestSubscriptionCallbackError = (0, _react.useRef)();
var latestSelector = (0, _react.useRef)();
var latestSelectedState = (0, _react.useRef)();
var selectedState;
try {
if (selector !== latestSelector.current || latestSubscriptionCallbackError.current) {
selectedState = selector(store.getState());
} else {
selectedState = latestSelectedState.current;
}
} catch (err) {
var errorMessage = "An error occurred while selecting the store state: " + err.message + ".";
if (latestSubscriptionCallbackError.current) {
errorMessage += "\nThe error may be correlated with this previous error:\n" + latestSubscriptionCallbackError.current.stack + "\n\nOriginal stack trace:";
}
throw new Error(errorMessage);
}
(0, _useIsomorphicLayoutEffect.useIsomorphicLayoutEffect)(function () {
latestSelector.current = selector;
latestSelectedState.current = selectedState;
latestSubscriptionCallbackError.current = undefined;
});
(0, _useIsomorphicLayoutEffect.useIsomorphicLayoutEffect)(function () {
function checkForUpdates() {
try {
var newSelectedState = latestSelector.current(store.getState());
if (equalityFn(newSelectedState, latestSelectedState.current)) {
return;
}
latestSelectedState.current = newSelectedState;
} catch (err) {
// we ignore all errors here, since when the component
// is re-rendered, the selectors are called again, and
// will throw again, if neither props nor store state
// changed
latestSubscriptionCallbackError.current = err;
}
forceRender({});
}
subscription.onStateChange = checkForUpdates;
subscription.trySubscribe();
checkForUpdates();
return function () {
return subscription.tryUnsubscribe();
};
}, [store, subscription]);
return selectedState;
}
/**
* Hook factory, which creates a `useSelector` hook bound to a given context.
*
* @param {Function} [context=ReactReduxContext] Context passed to your `<Provider>`.
* @returns {Function} A `useSelector` hook bound to the specified context.
*/
function createSelectorHook(context) {
if (context === void 0) {
context = _Context.ReactReduxContext;
}
var useReduxContext = context === _Context.ReactReduxContext ? _useReduxContext2.useReduxContext : function () {
return (0, _react.useContext)(context);
};
return function useSelector(selector, equalityFn) {
if (equalityFn === void 0) {
equalityFn = refEquality;
}
(0, _invariant["default"])(selector, "You must pass a selector to useSelectors");
var _useReduxContext = useReduxContext(),
store = _useReduxContext.store,
contextSub = _useReduxContext.subscription;
return useSelectorWithStoreAndSubscription(selector, equalityFn, store, contextSub);
};
}
/**
* A hook to access the redux store's state. This hook takes a selector function
* as an argument. The selector is called with the store state.
*
* This hook takes an optional equality comparison function as the second parameter
* that allows you to customize the way the selected state is compared to determine
* whether the component needs to be re-rendered.
*
* @param {Function} selector the selector function
* @param {Function=} equalityFn the function that will be used to determine equality
*
* @returns {any} the selected state
*
* @example
*
* import React from 'react'
* import { useSelector } from 'react-redux'
*
* export const CounterComponent = () => {
* const counter = useSelector(state => state.counter)
* return <div>{counter}</div>
* }
*/
var useSelector = createSelectorHook();
exports.useSelector = useSelector;