Handle Express Router imports after block comment banners

CHANGELOG.md

@@ -2,6 +2,8 @@
 
 ## 0.3.1 - Unreleased
 
+- Fixed Express route mapping for aliased Router imports that follow block comment banners, thanks @rohitjavvadi.
+
 ## 0.3.0 - 2026-05-18
 
 - Added a `pi` provider for routing review, fix, revalidate, and agent map through the [pi coding agent](https://pi.dev) in non-interactive print mode, thanks @danielmarbach.

src/mapper.test.ts

@@ -1755,11 +1755,31 @@ describe("mapFeatures", () => {
       "src/server.ts",
       [
         "// route imports",
+        "import { Router as OtherRouter } from 'other-router';",
+        "/* import { Router as CommentedOutRouter } from 'express'; */",
+        "/* import banner */ import { Router as BannerRouter } from 'express';",
+        "/*",
+        " * multiline import banner",
+        " */ import { Router as MultilineBannerRouter } from 'express';",
+        "import unused from 'unused'; /* stacked */ /* import banner */ import { Router as SemicolonBannerRouter } from 'express';",
+        "import from, { Router as FromBindingRouter } from 'express';",
+        "import 'reflect-metadata'",
+        "import/* type banner */type { Router as CommentedTypeRouter } from 'express';",
         "import express, { Router, Router as ExpressRouter } from 'express';",
         "",
+        "const config = { import: true }",
+        "export type { Router as ExportedTypeRouter } from 'express';",
         "const app = express();",
+        "const otherRouter = OtherRouter();",
+        "const commentedOutRouter = CommentedOutRouter();",
         "const router = Router();",
         "const aliasRouter = ExpressRouter();",
+        "const bannerRouter = BannerRouter();",
+        "const multilineBannerRouter = MultilineBannerRouter();",
+        "const semicolonBannerRouter = SemicolonBannerRouter();",
+        "const fromBindingRouter = FromBindingRouter();",
+        "const commentedTypeRouter = CommentedTypeRouter();",
+        "const exportedTypeRouter = ExportedTypeRouter();",
         "const typedRouter: Router = Router();",
         "const projectRouter = Router({ mergeParams: true });",
         "let hitCount = 0;",
@@ -1770,8 +1790,16 @@ describe("mapFeatures", () => {
         "app.get('/anonymous', requireAuth, (_req, res) => res.send('ok'));",
         "app.get('/dynamic/' + version, dynamicRoute);",
         "app.all('/proxy', proxy);",
+        "otherRouter.get('/other-router', ignoredOtherRouter);",
+        "commentedOutRouter.get('/commented-out-router', ignoredCommentedOutRouter);",
         "router.post('/admin/jobs', createJob);",
         "aliasRouter.get('/aliased-router', listAliasedRouter);",
+        "bannerRouter.get('/banner-router', listBannerRouter);",
+        "multilineBannerRouter.get('/multiline-banner-router', listMultilineBannerRouter);",
+        "semicolonBannerRouter.get('/semicolon-banner-router', listSemicolonBannerRouter);",
+        "fromBindingRouter.get('/from-binding-router', listFromBindingRouter);",
+        "commentedTypeRouter.get('/commented-type-router', ignoredCommentedTypeRouter);",
+        "exportedTypeRouter.get('/exported-type-router', ignoredExportedTypeRouter);",
         "router.post<{ Body: CreateJob }>('/typed-jobs', createTypedJob);",
         "typedRouter.patch('/typed/:id', updateTyped);",
         "router.route('/users').get(listUsers).delete(deleteUsers);",
@@ -1789,8 +1817,16 @@ describe("mapFeatures", () => {
         "function showAdmin() {}",
         "function dynamicRoute() {}",
         "function proxy() {}",
+        "function ignoredOtherRouter() {}",
+        "function ignoredCommentedOutRouter() {}",
         "function createJob() {}",
         "function listAliasedRouter() {}",
+        "function listBannerRouter() {}",
+        "function listMultilineBannerRouter() {}",
+        "function listSemicolonBannerRouter() {}",
+        "function listFromBindingRouter() {}",
+        "function ignoredCommentedTypeRouter() {}",
+        "function ignoredExportedTypeRouter() {}",
         "function createTypedJob() {}",
         "function updateTyped() {}",
         "function listUsers() {}",
@@ -1964,6 +2000,10 @@ describe("mapFeatures", () => {
         "Express route ALL /proxy",
         "Express route POST /admin/jobs",
         "Express route GET /aliased-router",
+        "Express route GET /banner-router",
+        "Express route GET /multiline-banner-router",
+        "Express route GET /semicolon-banner-router",
+        "Express route GET /from-binding-router",
         "Express route GET /cjs-aliased-router",
         "Express route GET /assigned-router",
         "Express route GET /typed-assigned-router",
@@ -1990,6 +2030,10 @@ describe("mapFeatures", () => {
     expect(titles).not.toContain("Express route GET /regex-health");
     expect(titles).not.toContain("Express route GET /arrow-regex");
     expect(titles).not.toContain("Express route GET /returned-regex");
+    expect(titles).not.toContain("Express route GET /other-router");
+    expect(titles).not.toContain("Express route GET /commented-out-router");
+    expect(titles).not.toContain("Express route GET /commented-type-router");
+    expect(titles).not.toContain("Express route GET /exported-type-router");
     expect(titles).not.toContain("Express route GET /custom-import-router");
     expect(titles).not.toContain("Express route GET /custom-router");
     expect(titles).not.toContain("Express route GET /custom-alias-router");

src/mappers/node-routes.ts

@@ -335,19 +335,72 @@ function expressRouterFactoryNames(source: string): Set<string> {
 
 function expressRouterImportBindingNames(source: string): Set<string> {
   const names = new Set<string>();
-  const pattern =
-    /(?:^|[;\n])\s*import\s+(?!type\b)((?:(?!\n\s*import\b)[\s\S]){0,400}?)\bfrom\s*["']express["']/gu;
+  const pattern = /\bimport\b/gu;
   pattern.lastIndex = 0;
   for (const match of source.matchAll(pattern)) {
-    const importIndex = source.indexOf("import", match.index ?? 0);
-    if (importIndex < 0 || isInsideCommentOrString(source, importIndex)) {
+    const importIndex = match.index ?? 0;
+    if (isInsideCommentOrString(source, importIndex)) {
       continue;
     }
-    addExpressRouterImportNames(names, match[1] ?? "");
+    const clause = readExpressStaticImportClause(source, importIndex);
+    if (clause !== null) {
+      addExpressRouterImportNames(names, clause);
+    }
   }
   return names;
 }
 
+function readExpressStaticImportClause(source: string, importIndex: number): string | null {
+  let cursor = importIndex + "import".length;
+  cursor = skipWhitespaceAndComments(source, cursor);
+  if (
+    source[cursor] === "(" ||
+    source[cursor] === "." ||
+    source[cursor] === "'" ||
+    source[cursor] === '"' ||
+    (source.startsWith("type", cursor) && !isIdentifierChar(source[cursor + "type".length]))
+  ) {
+    return null;
+  }
+  if (!isImportClauseStart(source[cursor])) {
+    return null;
+  }
+  const clauseStart = cursor;
+  const limit = Math.min(source.length, importIndex + 500);
+  while (cursor < limit) {
+    const char = source[cursor];
+    const next = source[cursor + 1];
+    if (char === undefined) {
+      break;
+    }
+    if (char === ";") {
+      return null;
+    }
+    if (char === "/" && next === "/") {
+      cursor = skipLineComment(source, cursor + 2);
+      continue;
+    }
+    if (char === "/" && next === "*") {
+      cursor = skipBlockComment(source, cursor + 2);
+      continue;
+    }
+    if (char === "'" || char === '"' || char === "`") {
+      cursor = skipQuoted(source, cursor, char);
+      continue;
+    }
+    if (isKeywordAt(source, cursor, "from")) {
+      const specifier = readImportSpecifier(source, cursor + "from".length);
+      if (specifier === null) {
+        cursor += "from".length;
+        continue;
+      }
+      return specifier.value === "express" ? source.slice(clauseStart, cursor) : null;
+    }
+    cursor += 1;
+  }
+  return null;
+}
+
 function addExpressRouterImportNames(names: Set<string>, clause: string): void {
   const named = /\{([^}]*)\}/u.exec(clause)?.[1];
   if (named === undefined) {
@@ -484,6 +537,22 @@ function expressChainMethods(source: string, start: number): string[] {
   return methods;
 }
 
+function isKeywordAt(source: string, index: number, keyword: string): boolean {
+  return (
+    source.startsWith(keyword, index) &&
+    !isIdentifierChar(source[index - 1]) &&
+    !isIdentifierChar(source[index + keyword.length])
+  );
+}
+
+function isIdentifierChar(char: string | undefined): boolean {
+  return char !== undefined && /[A-Za-z0-9_$]/u.test(char);
+}
+
+function isImportClauseStart(char: string | undefined): boolean {
+  return char !== undefined && (char === "{" || char === "*" || /[A-Za-z_$]/u.test(char));
+}
+
 function skipWhitespace(source: string, start: number): number {
   let cursor = start;
   while (/\s/u.test(source[cursor] ?? "")) {
@@ -492,6 +561,82 @@ function skipWhitespace(source: string, start: number): number {
   return cursor;
 }
 
+function skipWhitespaceAndComments(source: string, start: number): number {
+  let cursor = start;
+  while (cursor < source.length) {
+    const next = skipWhitespace(source, cursor);
+    if (source[next] === "/" && source[next + 1] === "*") {
+      cursor = skipBlockComment(source, next + 2);
+      continue;
+    }
+    if (source[next] === "/" && source[next + 1] === "/") {
+      cursor = skipLineComment(source, next + 2);
+      continue;
+    }
+    return next;
+  }
+  return cursor;
+}
+
+function skipLineComment(source: string, start: number): number {
+  const newline = source.indexOf("\n", start);
+  return newline < 0 ? source.length : newline + 1;
+}
+
+function skipBlockComment(source: string, start: number): number {
+  const close = source.indexOf("*/", start);
+  return close < 0 ? source.length : close + 2;
+}
+
+function skipQuoted(source: string, start: number, quote: string): number {
+  let cursor = start + 1;
+  let escaped = false;
+  while (cursor < source.length) {
+    const char = source[cursor];
+    if (char === undefined) {
+      break;
+    }
+    if (escaped) {
+      escaped = false;
+    } else if (char === "\\") {
+      escaped = true;
+    } else if (char === quote) {
+      return cursor + 1;
+    }
+    cursor += 1;
+  }
+  return source.length;
+}
+
+function readImportSpecifier(source: string, start: number): { value: string; end: number } | null {
+  let cursor = skipWhitespace(source, start);
+  const quote = source[cursor];
+  if (quote !== "'" && quote !== '"') {
+    return null;
+  }
+  cursor += 1;
+  let value = "";
+  let escaped = false;
+  while (cursor < source.length) {
+    const char = source[cursor];
+    if (char === undefined) {
+      break;
+    }
+    if (escaped) {
+      value += char;
+      escaped = false;
+    } else if (char === "\\") {
+      escaped = true;
+    } else if (char === quote) {
+      return { value, end: cursor + 1 };
+    } else {
+      value += char;
+    }
+    cursor += 1;
+  }
+  return null;
+}
+
 function nextRouteValueDelimiter(source: string, start: number): string | null {
   let cursor = start;
   while (cursor < source.length) {