add undefinedToVoid optional transformer

2015-01-02 00:41:33 +11:00
parent 41d60a85e9
commit 777f2be14e
1 changed files with 9 additions and 0 deletions
--- a/lib/6to5/transformation/transformers/optional-undefined-to-void.js
+++ b/lib/6to5/transformation/transformers/optional-undefined-to-void.js
@@ -0,0 +1,9 @@
+var t = require("../../types");
+
+exports.optional = true;
+
+exports.Identifier = function (node, parent) {
+  if (node.name === "undefined" && t.isReferenced(node, parent)) {
+    return t.unaryExpression("void", t.literal(0), true);
+  }
+};