repl: include folder extensions in autocomplete

When autocompleting `require` calls, the repl strips .js file extensions
from results. However, stripping an extension from a directory results
in an error. Update the autocompletion logic to avoid stripping
extensions from directories.

PR-URL: https://github.com/nodejs/node/pull/14727
Fixes: https://github.com/nodejs/node/issues/14726
Reviewed-By: Rich Trott <rtrott@gmail.com>
Reviewed-By: Benjamin Gruenbaum <benjamingr@gmail.com>
Reviewed-By: Timothy Gu <timothygu99@gmail.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Tobias Nießen <tniessen@tnie.de>
Reviewed-By: Yuta Hiroto <hello@about-hiroppy.com>
Reviewed-By: Alexey Orlenko <eaglexrlnk@gmail.com>

lib/repl.js

@@ -822,7 +822,7 @@ function complete(line, callback) {
     completeOn = match[1];
     var subdir = match[2] || '';
     filter = match[1];
-    var dir, files, f, name, base, ext, abs, subfiles, s;
+    var dir, files, f, name, base, ext, abs, subfiles, s, isDirectory;
     group = [];
     let paths = [];
 
@@ -851,23 +851,26 @@ function complete(line, callback) {
           // Exclude versioned names that 'npm' installs.
           continue;
         }
-        if (exts.indexOf(ext) !== -1) {
-          if (!subdir || base !== 'index') {
-            group.push(subdir + base);
-          }
-        } else {
         abs = path.resolve(dir, name);
         try {
-            if (fs.statSync(abs).isDirectory()) {
+          isDirectory = fs.statSync(abs).isDirectory();
+        } catch (e) {
+          continue;
+        }
+        if (isDirectory) {
           group.push(subdir + name + '/');
+          try {
             subfiles = fs.readdirSync(abs);
+          } catch (e) {
+            continue;
+          }
           for (s = 0; s < subfiles.length; s++) {
             if (indexRe.test(subfiles[s])) {
               group.push(subdir + name);
             }
           }
-            }
-          } catch (e) {}
+        } else if (exts.includes(ext) && (!subdir || base !== 'index')) {
+          group.push(subdir + base);
         }
       }
     }

test/parallel/test-repl-tab-complete.js

@@ -279,6 +279,16 @@ testMe.complete('require(\'n', common.mustCall(function(error, data) {
     });
   });
 
+  {
+    const path = '../fixtures/repl-folder-extensions/f';
+    testMe.complete(`require('${path}`, common.mustCall((err, data) => {
+      assert.ifError(err);
+      assert.strictEqual(data.length, 2);
+      assert.strictEqual(data[1], path);
+      assert.ok(data[0].includes('../fixtures/repl-folder-extensions/foo.js'));
+    }));
+  }
+
   process.chdir(cwd);
 }