move instanceof functionality to separate plugin - fixes #2745

packages/babel-plugin-transform-es2015-instanceof/src/index.js

@@ -0,0 +1,12 @@
+export default function ({ types: t }) {
+  return {
+    visitor: {
+      BinaryExpression(path) {
+        let { node } = path;
+        if (node.operator === "instanceof") {
+          path.replaceWith(t.callExpression(this.addHelper("instanceof"), [node.left, node.right]));
+        }
+      }
+    }
+  };
+}