[Checkbox][Switch] Remove checked argument from onChange

docs/src/pages/guides/migration-v4/migration-v4.md

@@ -1121,6 +1121,21 @@ As the core components use emotion as a styled engine, the props used by emotion
   </SvgIcon>
   ```
 
+### Switch
+
+- Remove the second argument from `onChange`. You can pull out the checked state by accessing `event.target.checked`.
+
+  ```diff
+  function MySwitch() {
+  - const handleChange = (event: any, checked: boolean) => {
+  + const handleChange = (event: any) => {
+  +   const checked = event.target.checked;
+    };
+
+    return <Switch onChange={handleChange} />;
+  }
+  ```
+
 ### Table
 
 - The customization of the table pagination's actions labels must be done with the `getItemAriaLabel` prop. This increases consistency with the `Pagination` component.

packages/material-ui/src/internal/SwitchBase.d.ts

@@ -52,7 +52,7 @@ export interface SwitchBaseProps
    * You can pull out the new value by accessing `event.target.value` (string).
    * You can pull out the new checked state by accessing `event.target.checked` (boolean).
    */
-  onChange?: (event: React.ChangeEvent<HTMLInputElement>, checked: boolean) => void;
+  onChange?: (event: React.ChangeEvent<HTMLInputElement>) => void;
   readOnly?: boolean;
   /**
    * If `true`, the `input` element is required.

packages/material-ui/src/internal/SwitchBase.js

@@ -100,13 +100,10 @@ const SwitchBase = React.forwardRef(function SwitchBase(props, ref) {
       return;
     }
 
-    const newChecked = event.target.checked;
-
-    setCheckedState(newChecked);
+    setCheckedState(event.target.checked);
 
     if (onChange) {
-      // TODO v5: remove the second argument.
-      onChange(event, newChecked);
+      onChange(event);
     }
   };
 

packages/material-ui/src/internal/SwitchBase.test.js

@@ -196,7 +196,7 @@ describe('<SwitchBase />', () => {
     it('should call onChange when controlled', () => {
       const checked = true;
       const handleChange = spy();
-      const { getByRole } = render(
+      const { getByRole, setProps } = render(
         <SwitchBase
           icon="unchecked"
           checkedIcon="checked"
@@ -207,9 +207,10 @@ describe('<SwitchBase />', () => {
       );
 
       getByRole('checkbox').click();
+      setProps({ checked: false });
 
       expect(handleChange.callCount).to.equal(1);
-      expect(handleChange.firstCall.args[1]).to.equal(!checked);
+      expect(handleChange.firstCall.args[0].target.checked).to.equal(!checked);
     });
 
     it('should not change checkbox state when event is default prevented', () => {