From 539222261baa1120c20a3f4ed020ecbd60a1f01b Mon Sep 17 00:00:00 2001
From: Chandler Prall <chandler.prall@gmail.com>
Date: Tue, 11 Dec 2018 12:21:56 -0700
Subject: [PATCH] Support null & undefined as proptype literals

---
 .../babel/proptypes-from-ts-props/index.js    | 18 +++++++++++----
 .../proptypes-from-ts-props/index.test.js     | 23 +++++++++++++++++++
 2 files changed, 37 insertions(+), 4 deletions(-)

diff --git a/scripts/babel/proptypes-from-ts-props/index.js b/scripts/babel/proptypes-from-ts-props/index.js
index 25387ae3926f..12b3144bf4ff 100644
--- a/scripts/babel/proptypes-from-ts-props/index.js
+++ b/scripts/babel/proptypes-from-ts-props/index.js
@@ -355,7 +355,7 @@ function getPropTypesForNode(node, optional, state) {
 
       const reducedUnionTypes = tsUnionTypes.reduce(
         (foundTypes, tsUnionType) => {
-          if (types.isLiteral(tsUnionType)) {
+          if (types.isLiteral(tsUnionType) || (types.isIdentifier(tsUnionType) && tsUnionType.name === 'undefined')) {
             if (foundTypes.oneOfPropType == null) {
               foundTypes.oneOfPropType = types.arrayExpression([]);
               foundTypes.unionTypes.push(
@@ -511,10 +511,20 @@ function getPropTypesForNode(node, optional, state) {
       optional = true; // cannot call `.isRequired` on a boolean literal
       break;
 
+    case 'TSNullKeyword':
+      propType =  types.nullLiteral();
+      optional = true; // cannot call `.isRequired` on a boolean literal
+      break;
+
+    case 'TSUndefinedKeyword':
+      propType =  types.identifier('undefined');
+      optional = true; // cannot call `.isRequired` on a boolean literal
+      break;
+
     // very helpful debugging code
-    // default:
-    //   debugger;
-    //   throw new Error(`Could not generate prop types for node type ${node.type}`);
+    default:
+      debugger;
+      throw new Error(`Could not generate prop types for node type ${node.type}`);
   }
 
   // if the node was unable to be translated to a prop type, fallback to PropTypes.any
diff --git a/scripts/babel/proptypes-from-ts-props/index.test.js b/scripts/babel/proptypes-from-ts-props/index.test.js
index 88a6f0473f9f..b7ae6d2f108a 100644
--- a/scripts/babel/proptypes-from-ts-props/index.test.js
+++ b/scripts/babel/proptypes-from-ts-props/index.test.js
@@ -977,6 +977,29 @@ FooComponent.propTypes = {
 };`);
       });
 
+      it('treats null and undefined as literals', () => {
+        const result = transform(
+          `
+import React from 'react';
+interface IFooProps {bar: 'five' | null | undefined}
+const FooComponent: React.SFC<IFooProps> = () => {
+  return (<div>Hello World</div>);
+}`,
+          babelOptions
+        );
+
+        expect(result.code).toBe(`import React from 'react';
+import PropTypes from "prop-types";
+
+const FooComponent = () => {
+  return <div>Hello World</div>;
+};
+
+FooComponent.propTypes = {
+  bar: PropTypes.oneOf(["five", null, undefined]).isRequired
+};`);
+      });
+
     });
 
     describe('array / arrayOf propTypes', () => {