JS: Try to guess the main file if only a .d.ts file was found

Author: asgerf

javascript/ql/lib/semmle/javascript/internal/paths/PackageJsonEx.qll

@@ -55,12 +55,9 @@ class PackageJsonEx extends PackageJson {
   File getMainFileOrBestGuess() {
     result = this.getMainFile()
     or
-    not exists(this.getMainFile()) and
-    (
-      result = guessPackageJsonMain1(this)
-      or
-      result = guessPackageJsonMain2(this)
-    )
+    result = guessPackageJsonMain1(this)
+    or
+    result = guessPackageJsonMain2(this)
   }
 
   string getAPathInFilesArray() {
@@ -116,8 +113,10 @@ private module Resolver = Folder::Resolve<ResolverConfig>;
 bindingset[name]
 private string stripPackageScope(string name) { result = name.regexpReplaceAll("^@[^/]+/", "") }
 
+private predicate isImplementationFile(File f) { not f.getBaseName().matches("%.d.ts") }
+
 File guessPackageJsonMain1(PackageJsonEx pkg) {
-  not exists(pkg.getMainFile()) and
+  not isImplementationFile(pkg.getMainFile()) and
   exists(Folder folder, Folder subfolder |
     folder = pkg.getFolder() and
     (
@@ -137,7 +136,7 @@ File guessPackageJsonMain1(PackageJsonEx pkg) {
 }
 
 File guessPackageJsonMain2(PackageJsonEx pkg) {
-  not exists(pkg.getMainFile()) and
-  not exists(guessPackageJsonMain1(pkg)) and
+  not isImplementationFile(pkg.getMainFile()) and
+  not isImplementationFile(guessPackageJsonMain1(pkg)) and
   result = pkg.getAFileInFilesArray()
 }