Change how lint rule is disabled

types/markdown-to-jsx/index.d.ts

@@ -10,6 +10,8 @@ export default class Markdown extends React.Component<MarkdownProps> { }
 
 export interface MarkdownProps {
     options?: MarkdownOptions;
+    // React.ReactNode contains both null and undefined
+    // tslint:disable-next-line:no-null-undefined-union
     children?: React.ReactNode;
 }
 
@@ -66,7 +68,10 @@ export interface MarkdownOptions {
     /** Custom React.createElement behavior. */
     createElement?: <P extends {}>(
         type: React.SFC<P> | React.ComponentClass<P> | string,
+        // This typing is copied from React
+        // tslint:disable-next-line:no-null-undefined-union
         props?: React.Attributes & P | null,
+        // tslint:disable-next-line:no-null-undefined-union
         ...children: React.ReactNode[]) => React.ReactElement<P>;
 
     /** Custom function to generate an HTML id from headings. */

types/markdown-to-jsx/markdown-to-jsx-tests.tsx

@@ -48,7 +48,10 @@ render(
         options={{
             createElement: <P extends {}>(
                 type: React.FunctionComponent<P> | React.ComponentClass<P> | string,
+                // This typing is copied from React
+                // tslint:disable-next-line:no-null-undefined-union
                 props?: React.Attributes & P | null,
+                // tslint:disable-next-line:no-null-undefined-union
                 ...children: React.ReactNode[]) => (
                     <div className="parent">
                         {React.createElement(type, props, children)}

types/markdown-to-jsx/tslint.json

@@ -1,6 +1,3 @@
 {
-    "extends": "dtslint/dt.json",
-    "rules": {
-        "no-null-undefined-union": false
-    }
+    "extends": "dtslint/dt.json"
 }