add submit method to Form (#37979)

types/react-jsonschema-form/index.d.ts

@@ -56,7 +56,9 @@ declare module 'react-jsonschema-form' {
         acceptcharset?: string;
     }
 
-    export default class Form<T> extends React.Component<FormProps<T>> {}
+    export default class Form<T> extends React.Component<FormProps<T>> {
+                     submit: () => void;
+                   }
 
     export type UiSchema = {
         'ui:field'?: Field | string;

types/react-jsonschema-form/react-jsonschema-form-tests.tsx

@@ -173,3 +173,15 @@ export const withThemeExample = () => {
 export const additionalPropertyFlagExample = () => {
     return ADDITIONAL_PROPERTY_FLAG;
 };
+
+export const ExternalFormSubmissionExample = () => {
+  const formRef = React.useRef<Form<any>>(null);
+
+  return (
+    <Form schema={schema} ref={formRef}>
+      <button onClick={formRef.current ? formRef.current.submit : undefined}>
+        FancySubmitButton
+      </button>
+    </Form>
+  );
+};