Add Pass A Function To A useState Updater as a react til

react/pass-a-function-to-a-usestate-updater.md

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+# Pass A Function To A useState Updater
+
+Let's say you have a component with a toggle state:
+
+```javascript
+const [toggle, setToggle] = useState(false);
+```
+
+You can change the state of the toggle by directly passing a value to
+`setToggle`.
+
+```javascript
+setToggle(true);
+console.log(toggle);
+//=> true
+```
+
+Alternatively, you can pass a function to the updater. This is called a
+[_functional
+update_](https://reactjs.org/docs/hooks-reference.html#functional-updates). The
+updater will call the function with the previous state value and update the
+state to whatever the function returns.
+
+```javascript
+const handleToggle = (prevToggle) => {
+  return !prevToggle;
+}
+
+console.log(toggle);
+//=> true
+
+setToggle(handleToggle);
+
+console.log(toggle);
+//=> false
+```