New source found from dndbeyond.com

ddb_main/tools/js/smartComponents/Collapsible/Collapsible.tsx

@@ -1,4 +1,4 @@
-import * as React from "react";
+import { ReactNode, MouseEvent, PureComponent, PropsWithChildren } from "react";
 
 import {
   DarkChevronUpSvg,
@@ -7,9 +7,9 @@ import {
 } from "../Svg";
 import CollapsibleHeaderContent from "./CollapsibleHeaderContent";
 
-interface Props {
-  header: React.ReactNode;
-  headerFooter?: React.ReactNode;
+interface Props extends PropsWithChildren {
+  header: ReactNode;
+  headerFooter?: ReactNode;
   className: string;
   initiallyCollapsed: boolean;
   collapsed?: boolean;
@@ -24,7 +24,7 @@ interface State {
   isDarkMode: boolean;
 }
 
-export class Collapsible extends React.PureComponent<Props, State> {
+export class Collapsible extends PureComponent<Props, State> {
   static defaultProps = {
     initiallyCollapsed: true,
     className: "",
@@ -83,7 +83,7 @@ export class Collapsible extends React.PureComponent<Props, State> {
     }
   }
 
-  handleClick = (evt: React.MouseEvent): void => {
+  handleClick = (evt: MouseEvent): void => {
     evt.stopPropagation();
     const { onChangeHandler } = this.props;
 
@@ -114,7 +114,7 @@ export class Collapsible extends React.PureComponent<Props, State> {
       useBuilderStyles,
     } = this.props;
 
-    let headerContentNode: React.ReactNode;
+    let headerContentNode: ReactNode;
     if (typeof header === "string") {
       headerContentNode = <CollapsibleHeaderContent heading={header} />;
     } else {
@@ -135,7 +135,7 @@ export class Collapsible extends React.PureComponent<Props, State> {
       // not implements
     }
 
-    let chevronNode: React.ReactNode = <DisabledChevronDownSvg />;
+    let chevronNode: ReactNode = <DisabledChevronDownSvg />;
     if (!isCollapsed) {
       chevronNode =
         isDarkMode && !useBuilderStyles ? (

ddb_main/tools/js/smartComponents/Collapsible/CollapsibleHeading/CollapsibleHeading.tsx

@@ -1,6 +1,6 @@
-import * as React from "react";
+import { PureComponent, PropsWithChildren } from "react";
 
-export default class CollapsibleHeading extends React.PureComponent<{}, {}> {
+export default class CollapsibleHeading extends PureComponent<PropsWithChildren> {
   render() {
     return (
       <div className="ddbc-collapsible__heading">{this.props.children}</div>