feat: support for in

src/evaluate.ts

@@ -134,7 +134,9 @@ const evaluate_map = {
     for (const value in evaluate(node.right, scope)) {
       const new_scope = new Scope("loop", scope);
       new_scope.invasived = true;
-      scope.$declar(kind, name, value);
+
+      new_scope.$declar(kind, name, value);
+
       const result = evaluate(node.body, new_scope);
       if (result === BREAK_SINGAL) {
         break;

test/ForInStatement.test.ts

@@ -0,0 +1,27 @@
+import test from "ava";
+import * as fs from "fs";
+
+import vm from "../src/vm";
+
+test("ForInStatement-1", t => {
+  const sandbox: any = vm.createContext({});
+
+  const obj: any = vm.runInContext(
+    `
+const obj = {
+  1: false,
+  2: false
+};
+
+for (let attr in obj) {
+  obj[attr] = true;
+}
+
+module.exports = obj;
+  `,
+    sandbox
+  );
+
+  t.true(obj[1]);
+  t.true(obj[2]);
+});