test(mobile): parse Expo route exports

mobile/src/expo-route-module-boundary.test.ts

@@ -1,9 +1,11 @@
 import { readFileSync, readdirSync } from 'node:fs'
 import { fileURLToPath } from 'node:url'
-import { extname, join, relative } from 'node:path'
+import { basename, dirname, extname, join, relative } from 'node:path'
+import ts from 'typescript'
 import { describe, expect, it } from 'vitest'
 
 const appDirectory = fileURLToPath(new URL('../app', import.meta.url))
+const routeSourceExtensions = new Set(['.js', '.jsx', '.ts', '.tsx'])
 
 function sourceFiles(directory: string): string[] {
   return readdirSync(directory, { withFileTypes: true }).flatMap((entry) => {
@@ -12,11 +14,88 @@ function sourceFiles(directory: string): string[] {
   })
 }
 
+function isNonScreenExpoModule(path: string): boolean {
+  const fileName = basename(path)
+  if (/\+api(?:\.\w+)?\.[jt]sx?$/.test(fileName)) {
+    return true
+  }
+  return (
+    dirname(relative(appDirectory, path)) === '.' &&
+    /^\+(?:html|middleware|native-intent)\.[jt]sx?$/.test(fileName)
+  )
+}
+
+function hasDefaultExport(path: string, source: string): boolean {
+  const extension = extname(path)
+  const sourceFile = ts.createSourceFile(
+    path,
+    source,
+    ts.ScriptTarget.Latest,
+    true,
+    extension === '.jsx'
+      ? ts.ScriptKind.JSX
+      : extension === '.js'
+        ? ts.ScriptKind.JS
+        : extension === '.tsx'
+          ? ts.ScriptKind.TSX
+          : ts.ScriptKind.TS
+  )
+
+  return sourceFile.statements.some((statement) => {
+    if (ts.isExportAssignment(statement)) {
+      return !statement.isExportEquals
+    }
+    if (ts.isExportDeclaration(statement) && !statement.isTypeOnly && statement.exportClause) {
+      if (ts.isNamespaceExport(statement.exportClause)) {
+        return statement.exportClause.name.text === 'default'
+      }
+      return statement.exportClause.elements.some(
+        (element) => !element.isTypeOnly && element.name.text === 'default'
+      )
+    }
+    const modifiers = ts.canHaveModifiers(statement) ? ts.getModifiers(statement) : undefined
+    return (
+      !ts.isInterfaceDeclaration(statement) &&
+      !ts.isTypeAliasDeclaration(statement) &&
+      modifiers?.some((modifier) => modifier.kind === ts.SyntaxKind.DeclareKeyword) !== true &&
+      modifiers?.some((modifier) => modifier.kind === ts.SyntaxKind.ExportKeyword) === true &&
+      modifiers.some((modifier) => modifier.kind === ts.SyntaxKind.DefaultKeyword)
+    )
+  })
+}
+
 describe('Expo route module boundary', () => {
+  it('allows Expo modules that are not screen routes', () => {
+    expect(isNonScreenExpoModule(join(appDirectory, 'health+api.ts'))).toBe(true)
+    expect(isNonScreenExpoModule(join(appDirectory, 'health+api.ios.ts'))).toBe(true)
+    expect(isNonScreenExpoModule(join(appDirectory, '+html.tsx'))).toBe(true)
+    expect(isNonScreenExpoModule(join(appDirectory, '+middleware.ts'))).toBe(true)
+    expect(isNonScreenExpoModule(join(appDirectory, '+native-intent.ts'))).toBe(true)
+    expect(isNonScreenExpoModule(join(appDirectory, 'nested', '+middleware.ts'))).toBe(false)
+  })
+
+  it('recognizes syntax-level default exports', () => {
+    expect(hasDefaultExport('route.tsx', 'export default function Route() {}')).toBe(true)
+    expect(
+      hasDefaultExport('route.jsx', 'export default function Route() { return <View /> }')
+    ).toBe(true)
+    expect(hasDefaultExport('route.ts', "export { default } from './route-screen'")).toBe(true)
+    expect(hasDefaultExport('route.ts', "export { Route as default } from './route-screen'")).toBe(
+      true
+    )
+    expect(hasDefaultExport('support.ts', '// export default')).toBe(false)
+    expect(hasDefaultExport('support.ts', "const marker = 'export default'")).toBe(false)
+    expect(hasDefaultExport('support.ts', 'export default interface Support {}')).toBe(false)
+    expect(
+      hasDefaultExport('support.ts', "export type { Support as default } from './types'")
+    ).toBe(false)
+  })
+
   it('keeps support modules outside the app route directory', () => {
     const invalidRoutes = sourceFiles(appDirectory)
-      .filter((path) => ['.ts', '.tsx'].includes(extname(path)))
-      .filter((path) => !readFileSync(path, 'utf8').includes('export default'))
+      .filter((path) => routeSourceExtensions.has(extname(path)))
+      .filter((path) => !isNonScreenExpoModule(path))
+      .filter((path) => !hasDefaultExport(path, readFileSync(path, 'utf8')))
       .map((path) => relative(appDirectory, path))
 
     expect(invalidRoutes).toEqual([])