Allow apiSetting to come in as a string

packages/api-explorer/__tests__/index.test.jsx

@@ -133,6 +133,24 @@ describe('oas', () => {
     expect(explorer.find('Doc').get(0).props.oas).toBe(oas);
   });
 
+  it('should fetch it from `doc.api.apiSetting` if it is a string', () => {
+    const explorer = shallow(
+      <ApiExplorer
+        {...props}
+        oasFiles={{
+          'api-setting': oas,
+        }}
+        docs={[
+          Object.assign({}, baseDoc, {
+            api: { method: 'get', apiSetting: 'api-setting' },
+          }),
+        ]}
+      />,
+    );
+
+    expect(explorer.find('Doc').get(0).props.oas).toBe(oas);
+  });
+
   it('should set it to empty object', () => {
     const explorer = shallow(
       <ApiExplorer

packages/api-explorer/src/index.jsx

@@ -42,9 +42,15 @@ class ApiExplorer extends React.Component {
     }
   }
   getOas(doc) {
-    // Get the apiSetting id either from the category, or the api if api is set
+    // Get the apiSetting id from the following places:
+    // - category.apiSetting if set and populated
+    // - api.apiSetting if that's a string
+    // - api.apiSetting._id if that's set
     // This will return undefined if apiSetting is not set
-    const apiSetting = doc.category.apiSetting || (doc.api.apiSetting && doc.api.apiSetting._id);
+    const apiSetting =
+      doc.category.apiSetting ||
+      (typeof doc.api.apiSetting === 'string' && doc.api.apiSetting) ||
+      (typeof doc.api.apiSetting === 'object' && doc.api.apiSetting._id);
 
     return this.props.oasFiles[apiSetting];
   }