import * as React from 'react';
import { Props } from '../index';

export interface CollapseProps extends Props {
  defaultStyle?: React.CSSProperties;
  collapsed: boolean;
  springConfig?: Object;
  children?: React.ReactElement<any>;
  animate?: boolean;
}

declare const Collapse: React.ComponentClass<CollapseProps>;
export default Collapse;

import * as React from 'react';
import { Props } from '../index';

export interface CollapseProps extends Props {
  defaultStyle?: React.CSSProperties;
  collapsed: boolean;
  springConfig: Object;
  children?: React.ReactElement<any>;
  animate?: boolean;
}

declare const Collapse: React.ComponentClass<CollapseProps>;
export default Collapse;

--- 
+++ 
@@ -4,7 +4,7 @@
 export interface CollapseProps extends Props {
   defaultStyle?: React.CSSProperties;
   collapsed: boolean;
-  springConfig: Object;
+  springConfig?: Object;
   children?: React.ReactElement<any>;
   animate?: boolean;
 }
Typescript: Make `springConfig` of `Collapse` optional

Since it has a default value, it's not required to be set when using the component.