Source-loader: Fix preamble insertion

lib/source-loader/src/server/__snapshots__/build.test.js.snap

@@ -1,5 +1,15 @@
 // Jest Snapshot v1, https://goo.gl/fbAQLP
 
+exports[`insertAfterImports addon-notes 1`] = `
+"import React from 'react';
+
+import BaseButton from '../components/BaseButton';
+import markdownNotes from './notes/notes.md';
+INSERT
+
+const markdownString = '...';"
+`;
+
 exports[`insertAfterImports imports 1`] = `
 "import foo;
 import bar;
@@ -7,8 +17,24 @@ INSERT
 whatever;"
 `;
 
+exports[`insertAfterImports multi-line imports 1`] = `
+"import foo;
+import {
+  bar
+} from baz;
+INSERT
+whatever;"
+`;
+
 exports[`insertAfterImports no imports 1`] = `
 "INSERT
 foo bar;
 baz;"
 `;
+
+exports[`insertAfterImports single-line imports 1`] = `
+"import foo;
+import { bar } from baz;
+INSERT
+whatever;"
+`;

lib/source-loader/src/server/build.js

@@ -6,6 +6,9 @@ export function insertAfterImports(insert, source) {
   if (start === -1) {
     start = 0;
   } else {
+    if (/import\s+{/.test(source.slice(start + 1, start + 10))) {
+      start = source.indexOf('}', start + 1);
+    }
     start = 1 + source.indexOf('\n', start + 1);
   }
   const imports = source.slice(0, start);
@@ -49,7 +52,7 @@ var __LOCAL_DEPENDENCIES__ = ${JSON.stringify(localDependencies)};
 var __IDS_TO_FRAMEWORKS__ = ${JSON.stringify(idsToFrameworks)};
 /* eslint-enable no-unused-vars,@typescript-eslint/no-unused-vars */        
         `;
-        // const annotated = insertAfterImports(preamble, source);
+        // return insertAfterImports(preamble, source);
         return `${preamble}${source}`;
       }
     );

lib/source-loader/src/server/build.test.js

@@ -19,4 +19,36 @@ whatever;
     `.trim();
     expect(insertAfterImports(insert, hasImports)).toMatchSnapshot();
   });
+
+  it('single-line imports', () => {
+    const hasImports = `
+import foo;
+import { bar } from baz;
+whatever;
+    `.trim();
+    expect(insertAfterImports(insert, hasImports)).toMatchSnapshot();
+  });
+
+  it('multi-line imports', () => {
+    const hasImports = `
+import foo;
+import {
+  bar
+} from baz;
+whatever;
+    `.trim();
+    expect(insertAfterImports(insert, hasImports)).toMatchSnapshot();
+  });
+
+  it('addon-notes', () => {
+    const notesStory = `
+    import React from 'react';
+
+import BaseButton from '../components/BaseButton';
+import markdownNotes from './notes/notes.md';
+
+const markdownString = '...';
+    `.trim();
+    expect(insertAfterImports(insert, notesStory)).toMatchSnapshot();
+  });
 });