Merge pull request #25590 from storybookjs/shilman/fix-configfile-exp…

…ort-specifier

ConfigFile: Fix export specifiers
(cherry picked from commit cb97367)

code/lib/csf-tools/src/ConfigFile.test.ts

@@ -217,6 +217,17 @@ describe('ConfigFile', () => {
           )
         ).toEqual([{ directory: '../src', titlePrefix: 'Demo' }]);
       });
+      it('export specfier', () => {
+        expect(
+          getField(
+            ['foo'],
+            dedent`
+              const foo = 'bar';
+              export { foo };
+            `
+          )
+        ).toEqual('bar');
+      });
     });
   });
 
@@ -436,6 +447,24 @@ describe('ConfigFile', () => {
         `);
       });
     });
+
+    describe('export specifiers', () => {
+      it('found object', () => {
+        expect(
+          setField(
+            ['core', 'builder'],
+            'webpack5',
+            dedent`
+              const core = { builder: 'webpack4' };
+              export { core };
+            `
+          )
+        ).toMatchInlineSnapshot(`
+          const core = { builder: 'webpack5' };
+          export { core };
+        `);
+      });
+    });
   });
 
   describe('appendToArray', () => {

code/lib/csf-tools/src/ConfigFile.ts

@@ -78,10 +78,12 @@ const _getPathProperties = (path: string[], node: t.Node): t.ObjectProperty[] |
   }
   return undefined;
 };
-
 // eslint-disable-next-line @typescript-eslint/naming-convention
-const _findVarInitialization = (identifier: string, program: t.Program) => {
-  let init: t.Expression | null | undefined = null;
+const _findVarDeclarator = (
+  identifier: string,
+  program: t.Program
+): t.VariableDeclarator | null | undefined => {
+  let declarator: t.VariableDeclarator | null | undefined = null;
   let declarations: t.VariableDeclarator[] | null = null;
   program.body.find((node: t.Node) => {
     if (t.isVariableDeclaration(node)) {
@@ -92,20 +94,26 @@ const _findVarInitialization = (identifier: string, program: t.Program) => {
 
     return (
       declarations &&
-      declarations.find((decl: t.Node) => {
+      declarations.find((decl: t.VariableDeclarator) => {
         if (
           t.isVariableDeclarator(decl) &&
           t.isIdentifier(decl.id) &&
           decl.id.name === identifier
         ) {
-          init = decl.init;
+          declarator = decl;
           return true; // stop looking
         }
         return false;
       })
     );
   });
-  return init;
+  return declarator;
+};
+
+// eslint-disable-next-line @typescript-eslint/naming-convention
+const _findVarInitialization = (identifier: string, program: t.Program) => {
+  const declarator = _findVarDeclarator(identifier, program);
+  return declarator?.init;
 };
 
 // eslint-disable-next-line @typescript-eslint/naming-convention
@@ -213,6 +221,16 @@ export class ConfigFile {
                 self._exportDecls[exportName] = decl;
               }
             });
+          } else if (node.specifiers) {
+            // export { X };
+            node.specifiers.forEach((spec) => {
+              if (t.isExportSpecifier(spec) && t.isIdentifier(spec.exported)) {
+                const { name: exportName } = spec.exported;
+                const decl = _findVarDeclarator(exportName, parent as t.Program) as any;
+                self._exports[exportName] = decl.init;
+                self._exportDecls[exportName] = decl;
+              }
+            });
           } else {
             logger.warn(
               getCsfParsingErrorMessage({

code/lib/csf-tools/src/getStorySortParameter.ts

@@ -96,6 +96,9 @@ const parseDefault = (defaultExpr: t.Expression, program: t.Program): t.Expressi
 };
 
 export const getStorySortParameter = (previewCode: string) => {
+  // don't even try to process the file
+  if (!previewCode.includes('storySort')) return undefined;
+
   let storySort: t.Expression | undefined;
   const ast = babelParse(previewCode);
   traverse.default(ast, {