Merge pull request #13029 from storybookjs/fix/default-argtypes-infer…

…ence

Args: Fix args inference for null values

addons/docs/src/frameworks/react/jsxDecorator.test.tsx

@@ -148,9 +148,9 @@ describe('renderJsx', () => {
     };
 
     expect(renderJsx(<Container>yo dude</Container>, {})).toMatchInlineSnapshot(`
-      <div>
+      <Container className="super-container">
         yo dude
-      </div>
+      </Container>
     `);
   });
 });

lib/client-api/src/ensureArgTypes.ts

@@ -5,8 +5,6 @@ import { combineParameters } from './parameters';
 export const ensureArgTypes: ArgTypesEnhancer = (context) => {
   const { argTypes: userArgTypes = {}, args = {} } = context.parameters;
   if (!args) return userArgTypes;
-  const argTypes = mapValues(args, (arg, name) =>
-    arg !== null && typeof arg !== 'undefined' ? { name } : undefined
-  );
+  const argTypes = mapValues(args, (_arg, name) => ({ name }));
   return combineParameters(argTypes, userArgTypes);
 };

lib/client-api/src/story_store.test.ts

@@ -707,6 +707,30 @@ describe('preview.story_store', () => {
       expect(store.getRawStory('a', '1').parameters.argTypes).toEqual({ e: 'f', c: 'd' });
     });
 
+    it('automatically infers argTypes from args', () => {
+      const store = new StoryStore({ channel });
+      addStoryToStore(store, 'a', '1', () => 0, { args: { a: null, b: 'hello', c: 9 } });
+      expect(store.getRawStory('a', '1').parameters.argTypes).toMatchInlineSnapshot(`
+        Object {
+          "a": Object {
+            "name": "a",
+          },
+          "b": Object {
+            "name": "b",
+            "type": Object {
+              "name": "string",
+            },
+          },
+          "c": Object {
+            "name": "c",
+            "type": Object {
+              "name": "number",
+            },
+          },
+        }
+      `);  
+    });
+
     it('adds user and default enhancers', () => {
       const store = new StoryStore({ channel });
       expect(store._argTypesEnhancers.length).toBe(1);