diff --git a/runtime/syntax/javascript.yaml b/runtime/syntax/javascript.yaml
index 5a3fee2b..21596a2c 100644
--- a/runtime/syntax/javascript.yaml
+++ b/runtime/syntax/javascript.yaml
@@ -9,8 +9,8 @@ rules:
     - constant.number: "\\b[-+]?([0-9]+[EePp][+-]?[0-9]+)[fFlL]?"
     - identifier: "[A-Za-z_][A-Za-z0-9_]*[[:space:]]*[(]"
     - statement: "\\b(break|case|catch|continue|default|delete|do|else|finally)\\b"
-    - statement: "\\b(for|function|get|if|in|instanceof|new|return|set|switch)\\b"
-    - statement: "\\b(switch|this|throw|try|typeof|var|void|while|with)\\b"
+    - statement: "\\b(for|function|class|extends|get|if|in|instanceof|new|return|set|switch)\\b"
+    - statement: "\\b(switch|this|throw|try|typeof|var|const|let|void|while|with)\\b"
     - constant: "\\b(null|undefined|NaN)\\b"
     - constant: "\\b(true|false)\\b"
     - type: "\\b(Array|Boolean|Date|Enumerator|Error|Function|Math)\\b"