replace paths with cloned nodes in builtins transform (#579)

Author: vigneshshanmugam

packages/babel-plugin-minify-builtins/src/index.js

@@ -78,15 +78,13 @@ module.exports = function({ types: t }) {
           if (subpaths.length <= 1) {
             continue;
           }
-          const uniqueIdentifier = this.program.scope.generateUidIdentifier(
-            expName
-          );
+          const uniqueIdentifier = parent.scope.generateUidIdentifier(expName);
           const newNode = t.variableDeclaration("var", [
             t.variableDeclarator(uniqueIdentifier, subpaths[0].node)
           ]);
 
           for (const path of subpaths) {
-            path.replaceWith(uniqueIdentifier);
+            path.replaceWith(t.clone(uniqueIdentifier));
           }
           // hoist the created var to the top of the function scope
           parent.get("body").unshiftContainer("body", newNode);

packages/babel-preset-babili/__tests__/preset-tests.js

@@ -131,4 +131,20 @@ describe("preset", () => {
     `);
     expect(transform(source)).toBe(expected);
   });
+
+  it("should fix bug#568 - conflicts b/w builtIns and mangle", () => {
+    const source = unpad(`
+      (function () {
+        return [Math.pi, Math.pi];
+      })();
+    `);
+    const expected = unpad(`
+      (function () {
+        var a = Math.pi;
+
+        return [a, a];
+      })();
+    `);
+    expect(transform(source)).toBe(expected);
+  });
 });