5/17/2023 0 Comments Redux connect![]() ![]() Only returns a new object when one of the values has changed. Use Reselect or a similar library to create a memoized selector that returns multiple values in one object, but.Call useSelector() multiple times, with each call returning a single field value.If you want to retrieve multiple values from the store, you can: With useSelector(), returning a new objectĮvery time will always force a re-render by default. It didn't matter if the return object wasĪ new reference or not - connect() just compared the individual fields. With mapState, all individual fields were returned in a combined object. This has several implications on how you should use useSelector(). ![]() This is different than connect(), which uses shallow equality checks on the results of mapState calls The default comparison is a strict = referenceĬomparison. However, when an action is dispatched to the Redux store, useSelector() only forces a re-render if the selector resultĪppears to be different than the last result. (A cached result may be returned by the hook without re-running the selector if it's the same function reference as on a previous render of the component.) When the function component renders, the provided selector function will be called and its result will be returnedįrom the useSelector() hook. Because of the React update batching behavior used in React Redux v7, a dispatched action that causes multiple useSelector()s in the same component to return new values should only result in a single re-render. Each call to useSelector() creates an individual subscription to the Redux store. You may call useSelector() multiple times within a single function component. See the Usage Warnings section of this page for further details. There are potential edge cases with using props in selectors that may cause issues.
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