[Autocomplete] Update docs for defaultValue prop (mui#19431)

Author: willwill96

docs/pages/api/autocomplete.md

@@ -35,7 +35,7 @@ You can learn more about the difference by [reading this guide](/guides/minimizi
 | <span class="prop-name">closeIcon</span> | <span class="prop-type">node</span> | <span class="prop-default">&lt;CloseIcon fontSize="small" /></span> | The icon to display in place of the default close icon. |
 | <span class="prop-name">closeText</span> | <span class="prop-type">string</span> | <span class="prop-default">'Close'</span> | Override the default text for the *close popup* icon button.<br>For localization purposes, you can use the provided [translations](/guides/localization/). |
 | <span class="prop-name">debug</span> | <span class="prop-type">bool</span> | <span class="prop-default">false</span> | If `true`, the popup will ignore the blur event if the input if filled. You can inspect the popup markup with your browser tools. Consider this option when you need to customize the component. |
-| <span class="prop-name">defaultValue</span> | <span class="prop-type">any<br>&#124;&nbsp;array</span> |  | The default input value. Use when the component is not controlled. |
+| <span class="prop-name">defaultValue</span> | <span class="prop-type">any<br>&#124;&nbsp;array</span> | <span class="prop-default">props.multiple ? [] : null</span> | The default input value. Use when the component is not controlled. |
 | <span class="prop-name">disableClearable</span> | <span class="prop-type">bool</span> | <span class="prop-default">false</span> | If `true`, the input can't be cleared. |
 | <span class="prop-name">disableCloseOnSelect</span> | <span class="prop-type">bool</span> | <span class="prop-default">false</span> | If `true`, the popup won't close when a value is selected. |
 | <span class="prop-name">disabled</span> | <span class="prop-type">bool</span> | <span class="prop-default">false</span> | If `true`, the input will be disabled. |

packages/material-ui-lab/src/Autocomplete/Autocomplete.js

@@ -247,7 +247,7 @@ const Autocomplete = React.forwardRef(function Autocomplete(props, ref) {
     closeIcon = <CloseIcon fontSize="small" />,
     closeText = 'Close',
     debug = false,
-    defaultValue,
+    defaultValue = props.multiple ? [] : null,
     disableClearable = false,
     disableCloseOnSelect = false,
     disabled = false,

packages/material-ui-lab/src/useAutocomplete/useAutocomplete.js

@@ -85,7 +85,7 @@ export default function useAutocomplete(props) {
     blurOnSelect = false,
     clearOnEscape = false,
     debug = false,
-    defaultValue,
+    defaultValue = props.multiple ? [] : null,
     disableClearable = false,
     disableCloseOnSelect = false,
     disableListWrap = false,
@@ -193,7 +193,7 @@ export default function useAutocomplete(props) {
 
   const [value, setValue] = useControlled({
     controlled: valueProp,
-    default: defaultValue || (multiple ? [] : null),
+    default: defaultValue,
     name: componentName,
   });