Handle transformed HTML at the root route.

src/koa-node-resolve.ts

@@ -18,7 +18,7 @@ import {parse as parseURL} from 'url';
 import {moduleSpecifierTransform, ModuleSpecifierTransformOptions} from './koa-module-specifier-transform';
 import {prefixedLogger} from './support/logger';
 import {Logger} from './support/logger';
-import {noLeadingSlashInURL} from './support/path-utils';
+import {noLeadingSlashInURL, resolvePathPreserveTrailingSlash} from './support/path-utils';
 import {resolveNodeSpecifier} from './support/resolve-node-specifier';
 
 export {Logger} from './support/logger';
@@ -40,7 +40,7 @@ export const nodeResolve =
       return moduleSpecifierTransform(
           (baseURL: string, specifier: string, logger: Logger) =>
               resolveNodeSpecifier(
-                  resolvePath(
+                  resolvePathPreserveTrailingSlash(
                       resolvePath(options.root || '.'),
                       noLeadingSlashInURL(parseURL(baseURL).pathname || '/')),
                   specifier,

src/support/path-utils.ts

@@ -11,7 +11,7 @@
  * subject to an additional IP rights grant found at
  * http://polymer.github.io/PATENTS.txt
  */
-import {posix, sep as pathSeparator} from 'path';
+import {posix, resolve as resolvePath, sep as pathSeparator} from 'path';
 
 const filenameRegex = process.platform === 'win32' ? /[^\\]+$/ : /[^\/]+$/;
 
@@ -35,10 +35,22 @@ export const forwardSlashesOnlyPlease = (path: string): string =>
 
 export const getBaseURL = (href: string): string => href.replace(/[^\/]+$/, '');
 
+export const noTrailingSlashInPath = (path: string): string =>
+    path.replace(/\/$/, '');
+
 export const noLeadingSlashInURL = (href: string): string =>
     href.replace(/^\//, '');
 
 export const relativePathToURL = (from: string, to: string): string =>
     ensureLeadingDotInURL(posix.relative(
         getBaseURL(forwardSlashesOnlyPlease(from)),
         forwardSlashesOnlyPlease(to)));
+
+export const resolvePathPreserveTrailingSlash =
+    (from: string, to: string): string => {
+      const resolvedPath = resolvePath(from, to);
+      return isDirectorySpecifier(to) ? `${resolvedPath}/` : resolvedPath;
+    };
+
+const isDirectorySpecifier = (specifier: string) => ['', '.', '..'].includes(
+    specifier.match(/([^\/]*$)/)![0]);

src/test/koa-node-resolve.test.ts

@@ -11,15 +11,16 @@
  * subject to an additional IP rights grant found at
  * http://polymer.github.io/PATENTS.txt
  */
-import {resolve as resolvePath} from 'path';
 import request from 'supertest';
 import test from 'tape';
 
 import {nodeResolve} from '../koa-node-resolve';
+import {resolvePathPreserveTrailingSlash} from '../support/path-utils';
 
 import {createAndServe, squeeze, testLogger} from './test-utils';
 
-const fixturesPath = resolvePath(__dirname, '../../test/fixtures/');
+const fixturesPath =
+    resolvePathPreserveTrailingSlash(__dirname, '../../test/fixtures/');
 
 test('nodeResolve middleware transforms resolvable specifiers', async (t) => {
   t.plan(4);
@@ -63,6 +64,48 @@ test('nodeResolve middleware transforms resolvable specifiers', async (t) => {
       });
 });
 
+test('nodeResolve middleware works even if baseURL has no pathname', async (t) => {
+  t.plan(4);
+  const logger = testLogger();
+  createAndServe(
+      {
+        middleware:
+            [nodeResolve({root: fixturesPath, logger, logLevel: 'debug'})],
+        routes: {
+          '/my-module.js': `import * as x from 'x';`,
+          '/': `
+            <script type="module">
+            import * as x from 'x';
+            </script>
+          `,
+        },
+      },
+      async (server) => {
+        t.equal(
+            squeeze((await request(server).get('/my-module.js')).text),
+            squeeze(`
+              import * as x from './node_modules/x/main.js';
+            `),
+            'should transform specifiers in JavaScript module');
+        t.equal(
+            squeeze((await request(server).get('/')).text),
+            squeeze(`
+              <script type="module">
+              import * as x from './node_modules/x/main.js';
+              </script>
+            `),
+            'should transform specifiers in inline module script');
+        t.deepEqual(logger.debugs.map((args) => args.join(' ')), [
+          '[koa-node-resolve] Resolved Node module specifier "x" to "./node_modules/x/main.js"',
+          '[koa-node-resolve] Resolved Node module specifier "x" to "./node_modules/x/main.js"',
+        ]);
+        t.deepEqual(logger.infos.map((args) => args.join(' ')), [
+          '[koa-node-resolve] Transformed 1 module specifier(s) in "/my-module.js"',
+          '[koa-node-resolve] Transformed 1 module specifier(s) in "/"',
+        ]);
+      });
+});
+
 test('nodeResolve middleware ignores unresolvable specifiers', async (t) => {
   t.plan(2);
   const logger = testLogger();

src/test/path-utils.test.ts

@@ -0,0 +1,44 @@
+/**
+ * @license
+ * Copyright (c) 2020 The Polymer Project Authors. All rights reserved.
+ * This code may only be used under the BSD style license found at
+ * http://polymer.github.io/LICENSE.txt
+ * The complete set of authors may be found at
+ * http://polymer.github.io/AUTHORS.txt
+ * The complete set of contributors may be found at
+ * http://polymer.github.io/CONTRIBUTORS.txt
+ * Code distributed by Google as part of the polymer project is also
+ * subject to an additional IP rights grant found at
+ * http://polymer.github.io/PATENTS.txt
+ */
+import test from 'tape';
+
+import {dirname, resolvePathPreserveTrailingSlash} from '../support/path-utils';
+
+test('dirname returns portion of path representing directory', (t) => {
+  t.plan(2);
+  t.equal(
+      dirname('/a/b/c'),
+      '/a/b/',
+      'should treat lack of trailing slash as file');
+  t.equal(
+      dirname('/a/b/c/'),
+      '/a/b/c/',
+      'should treat segment before trailing slash as directory name');
+});
+
+test('resolvePathPreserveTrailingSlash may return trailing slash', (t) => {
+  t.plan(3);
+  t.equal(
+      resolvePathPreserveTrailingSlash('/a/b', 'c/'),
+      '/a/b/c/',
+      'should contain trailing slash when destination has trailing slash');
+  t.equal(
+      resolvePathPreserveTrailingSlash('/a/b', 'c'),
+      '/a/b/c',
+      'should not contain trailing slash if destination does not have trailing slash');
+  t.equal(
+      resolvePathPreserveTrailingSlash('/a/b', ''),
+      '/a/b/',
+      'should contain trailing slash if destination is current directory');
+});

src/test/resolve-node-specifier.test.ts

@@ -11,16 +11,15 @@
  * subject to an additional IP rights grant found at
  * http://polymer.github.io/PATENTS.txt
  */
-import {resolve as resolvePath} from 'path';
 import test from 'tape';
 
-import {ensureTrailingSlashInPath} from '../support/path-utils';
+import {resolvePathPreserveTrailingSlash} from '../support/path-utils';
 import {resolveNodeSpecifier} from '../support/resolve-node-specifier';
 import {testLogger} from './test-utils';
 
 const logger = testLogger();
 const fixturesPath =
-    ensureTrailingSlashInPath(resolvePath(__dirname, '../../test/fixtures/'));
+    resolvePathPreserveTrailingSlash(__dirname, '../../test/fixtures/');
 const resolve = (specifier: string): string =>
     resolveNodeSpecifier(fixturesPath, specifier, logger);
 

src/test/test-utils.ts

@@ -37,8 +37,8 @@ export const createApp = (options: AppOptions): Koa => {
       app.use(route.get(key, (ctx) => {
         if (key.endsWith('.js')) {
           ctx.type = 'js';
-        }
-        if (key.endsWith('.html')) {
+        } else {
+          // Assume everything else is html.
           ctx.type = 'html';
         }
         // Make our body a stream, like koa static would do, to make sure we