React: Improve error handling of component manifest generation

.gitignore

@@ -65,3 +65,5 @@ code/core/report
 node_modules/.svelte2tsx-language-server-files
 
 *storybook.log
+
+.junie

code/core/src/csf-tools/CsfFile.ts

@@ -33,7 +33,7 @@ interface BabelFile {
   opts: any;
   hub: any;
   metadata: object;
-  path: any;
+  path: NodePath<t.Program>;
   scope: any;
   inputMap: object | null;
   code: string;
@@ -297,10 +297,15 @@ export class CsfFile {
 
   _storyExports: Record<string, t.VariableDeclarator | t.FunctionDeclaration> = {};
 
+  _storyDeclarationPath: Record<string, NodePath<t.VariableDeclarator | t.FunctionDeclaration>> =
+    {};
+
   _storyPaths: Record<string, NodePath<t.ExportNamedDeclaration>> = {};
 
   _metaStatement: t.Statement | undefined;
 
+  _metaStatementPath: NodePath<t.Statement> | undefined;
+
   _metaNode: t.ObjectExpression | undefined;
 
   _metaPath: NodePath<t.ExportDefaultDeclaration> | undefined;
@@ -476,19 +481,24 @@ export class CsfFile {
             // export default meta;
             const variableName = (node.declaration as t.Identifier).name;
             self._metaVariableName = variableName;
-            const isVariableDeclarator = (declaration: t.VariableDeclarator) =>
+            const isMetaVariable = (declaration: t.VariableDeclarator) =>
               t.isIdentifier(declaration.id) && declaration.id.name === variableName;
 
-            self._metaStatement = self._ast.program.body.find(
-              (topLevelNode) =>
-                t.isVariableDeclaration(topLevelNode) &&
-                topLevelNode.declarations.find(isVariableDeclarator)
-            );
+            self._metaStatementPath = self._file.path
+              .get('body')
+              .find(
+                (path) =>
+                  path.isVariableDeclaration() && path.node.declarations.some(isMetaVariable)
+              );
+
+            self._metaStatement = self._metaStatementPath?.node;
+
             decl = ((self?._metaStatement as t.VariableDeclaration)?.declarations || []).find(
-              isVariableDeclarator
+              isMetaVariable
             )?.init;
           } else {
             self._metaStatement = node;
+            self._metaStatementPath = path;
             decl = node.declaration;
           }
 
@@ -529,23 +539,28 @@ export class CsfFile {
       ExportNamedDeclaration: {
         enter(path) {
           const { node, parent } = path;
+          const declaration = path.get('declaration');
           let declarations;
-          if (t.isVariableDeclaration(node.declaration)) {
-            declarations = node.declaration.declarations.filter((d) => t.isVariableDeclarator(d));
-          } else if (t.isFunctionDeclaration(node.declaration)) {
-            declarations = [node.declaration];
+          if (declaration.isVariableDeclaration()) {
+            declarations = declaration.get('declarations').filter((d) => d.isVariableDeclarator());
+          } else if (declaration.isFunctionDeclaration()) {
+            declarations = [declaration];
           }
           if (declarations) {
             // export const X = ...;
-            declarations.forEach((decl: t.VariableDeclarator | t.FunctionDeclaration) => {
-              if (t.isIdentifier(decl.id)) {
+            declarations.forEach((declPath) => {
+              const decl = declPath.node;
+              const id = declPath.node.id;
+
+              if (t.isIdentifier(id)) {
                 let storyIsFactory = false;
-                const { name: exportName } = decl.id;
-                if (exportName === '__namedExportsOrder' && t.isVariableDeclarator(decl)) {
-                  self._namedExportsOrder = parseExportsOrder(decl.init as t.Expression);
+                const { name: exportName } = id;
+                if (exportName === '__namedExportsOrder' && declPath.isVariableDeclarator()) {
+                  self._namedExportsOrder = parseExportsOrder(declPath.node.init as t.Expression);
                   return;
                 }
                 self._storyExports[exportName] = decl;
+                self._storyDeclarationPath[exportName] = declPath;
                 self._storyPaths[exportName] = path;
                 self._storyStatements[exportName] = node;
                 let name = storyNameFromExport(exportName);
@@ -1036,7 +1051,10 @@ export const babelParseFile = ({
   filename?: string;
   ast?: t.File;
 }): BabelFile => {
-  return new BabelFileClass({ filename }, { code, ast: ast ?? babelParse(code) });
+  return new BabelFileClass(
+    { filename, highlightCode: false },
+    { code, ast: ast ?? babelParse(code) }
+  );
 };
 
 export const loadCsf = (code: string, options: CsfOptions) => {

code/core/src/types/modules/core-common.ts

@@ -347,12 +347,14 @@ export type TagsOptions = Record<Tag, Partial<TagOptions>>;
 
 export interface ComponentManifest {
   id: string;
-  name: string;
+  path: string;
+  name?: string;
   description?: string;
   import?: string;
   summary?: string;
-  examples: { name: string; snippet: string }[];
+  examples: { name: string; snippet?: string; error?: { message: string } }[];
   jsDocTags: Record<string, string[]>;
+  error?: { message: string };
 }
 
 export interface ComponentsManifest {

code/renderers/react/src/componentManifest/generateCodeSnippet.test.tsx

@@ -1,7 +1,6 @@
 import { expect, test } from 'vitest';
 
 import { recast } from 'storybook/internal/babel';
-import type { NodePath } from 'storybook/internal/babel';
 import { types as t } from 'storybook/internal/babel';
 import { loadCsf } from 'storybook/internal/csf-tools';
 
@@ -13,10 +12,8 @@ function generateExample(code: string) {
   const csf = loadCsf(code, { makeTitle: (userTitle?: string) => userTitle ?? 'title' }).parse();
   const component = csf._meta?.component ?? 'Unknown';
 
-  const snippets = Object.values(csf._storyPaths)
-    .map((path: NodePath<t.ExportNamedDeclaration>) =>
-      getCodeSnippet(path, csf._metaNode ?? null, component)
-    )
+  const snippets = Object.entries(csf._storyDeclarationPath)
+    .map(([name, path]) => getCodeSnippet(path, name, csf._metaNode ?? null, component))
     .filter(Boolean);
 
   return recast.print(t.program(snippets)).code;
@@ -81,8 +78,15 @@ test('Edge case identifier we can not find', () => {
   const input = withCSF3(`
     export const Default = someImportOrWhatever;
   `);
-  expect(generateExample(input)).toMatchInlineSnapshot(
-    `"const Default = () => <Button>Click me</Button>;"`
+  expect(() => generateExample(input)).toThrowErrorMatchingInlineSnapshot(
+    `
+    [SyntaxError: Expected story to be csf factory, function or an object expression
+      11 |
+      12 |
+    > 13 |     export const Default = someImportOrWhatever;
+         |                            ^^^^^^^^^^^^^^^^^^^^
+      14 |   ]
+  `
   );
 });
 
@@ -248,7 +252,11 @@ test('CustomRenderBlockBody only', async () => {
     };`
   );
   expect(generateExample(input)).toMatchInlineSnapshot(
-    `"const CustomRenderBlockBody = (args) => { return <Button {...args}>Render</Button> };"`
+    `
+    "const CustomRenderBlockBody = () => {
+        return <Button foo="bar">Render</Button>;
+    };"
+  `
   );
 });
 
@@ -504,8 +512,29 @@ test('top level args injection and spreading in different places', async () => {
   `);
   expect(generateExample(input)).toMatchInlineSnapshot(`
     "const MultipleSpreads = () => <div count={0}>
-        <Button disabled={false} count={0} empty="" />
-        <Button disabled={false} count={0} empty="" />
+        <Button disabled={false} count={0} empty="">Click me</Button>
+        <Button disabled={false} count={0} empty="">Click me</Button>
     </div>;"
   `);
 });
+
+test('allow top level export functions', async () => {
+  const input = withCSF3(dedent`
+    export function Usage(args) {
+      return (
+        <div style={{ padding: 40 }}>
+          <Button {...args}></Button>
+        </div>
+      );
+    }
+  `);
+  expect(generateExample(input)).toMatchInlineSnapshot(`
+    "function Usage() {
+        return (
+            <div style={{ padding: 40 }}>
+                <Button>Click me</Button>
+            </div>
+        );
+    }"
+  `);
+});