diff --git a/javascript/extractor/src/com/semmle/js/extractor/AutoBuild.java b/javascript/extractor/src/com/semmle/js/extractor/AutoBuild.java
index 7b7433d8f56c..ca7fa6c06c0e 100644
--- a/javascript/extractor/src/com/semmle/js/extractor/AutoBuild.java
+++ b/javascript/extractor/src/com/semmle/js/extractor/AutoBuild.java
@@ -151,7 +151,7 @@
  *
  * <ul>
  *   <li>All JavaScript files, that is, files with one of the extensions supported by {@link
- *       FileType#JS} (currently ".js", ".jsx", ".mjs", ".cjs", ".es6", ".es").
+ *       FileType#JS} (currently ".js", ".jsx", ".mjs", ".cjs", ".es6", ".es", ".xsjs", ".xsjslib").
  *   <li>All HTML files, that is, files with with one of the extensions supported by {@link
  *       FileType#HTML} (currently ".htm", ".html", ".xhtm", ".xhtml", ".vue", ".html.erb", ".html.dot", ".jsp").
  *   <li>All YAML files, that is, files with one of the extensions supported by {@link
diff --git a/javascript/extractor/src/com/semmle/js/extractor/FileExtractor.java b/javascript/extractor/src/com/semmle/js/extractor/FileExtractor.java
index a64dcd46284a..207d531230ce 100644
--- a/javascript/extractor/src/com/semmle/js/extractor/FileExtractor.java
+++ b/javascript/extractor/src/com/semmle/js/extractor/FileExtractor.java
@@ -135,7 +135,7 @@ protected boolean contains(File f, String lcExt, ExtractorConfig config) {
       }
     },
 
-    JS(".js", ".jsx", ".mjs", ".cjs", ".es6", ".es") {
+    JS(".js", ".jsx", ".mjs", ".cjs", ".es6", ".es", ".xsjs", ".xsjslib") {
       @Override
       public IExtractor mkExtractor(ExtractorConfig config, ExtractorState state) {
         return new ScriptExtractor(config, state);
diff --git a/javascript/extractor/test/com/semmle/js/extractor/test/AutoBuildTests.java b/javascript/extractor/test/com/semmle/js/extractor/test/AutoBuildTests.java
index 46285275fb15..0a924d54319a 100644
--- a/javascript/extractor/test/com/semmle/js/extractor/test/AutoBuildTests.java
+++ b/javascript/extractor/test/com/semmle/js/extractor/test/AutoBuildTests.java
@@ -178,6 +178,8 @@ public void basicTest() throws IOException {
     addFile(true, LGTM_SRC, "tst.js");
     addFile(true, LGTM_SRC, "tst.ts");
     addFile(true, LGTM_SRC, "tst.html");
+    addFile(true, LGTM_SRC, "tst.xsjs");
+    addFile(true, LGTM_SRC, "tst.xsjslib");
     addFile(false, LGTM_SRC, "tst.json");
     addFile(true, LGTM_SRC, "package.json");
     addFile(true, LGTM_SRC, ".eslintrc.yml");