conditionally pass through the preset option rather than undefined

disintegrator · disintegrator · commit 70938cdeee74 · 2021-01-28T23:04:20.000Z
diff --git a/packages/babel-preset-gatsby/src/__tests__/index.js b/packages/babel-preset-gatsby/src/__tests__/index.js
@@ -40,4 +40,17 @@ describe(`babel-preset-gatsby`, () => {
       }),
     ])
   })
+
+  it(`Allows to configure react importSource`, () => {
+    const { presets } = preset(null, {
+      reactImportSource: `@emotion/react`,
+    })
+
+    expect(presets[1]).toEqual([
+      expect.stringContaining(path.join(`@babel`, `preset-react`)),
+      expect.objectContaining({
+        importSource: `@emotion/react`,
+      }),
+    ])
+  })
 })
diff --git a/packages/babel-preset-gatsby/src/index.js b/packages/babel-preset-gatsby/src/index.js
@@ -83,7 +83,9 @@ export default function preset(_, options = {}) {
               : `React.createElement`,
           development: stage === `develop`,
           runtime: options.reactRuntime || `classic`,
-          importSource: options.reactImportSource,
+          ...(options.reactImportSource
+            ? { importSource: options.reactImportSource }
+            : {}),
         },
       ],
     ],
