Proxy API usage scenarios —— Sandbox

sandbox.js

function sandbox(code) {
  code = "with (sandbox) {" + code + "}";
  const fn = new Function("sandbox", code);

  return function (sandbox) {
    const sandboxProxy = new Proxy(sandbox, {
      has(target, key) {
        return true;
      },
      get(target, key) {
        if (key === Symbol.unscopables) return undefined;
        return target[key];
      },
    });
    return fn(sandboxProxy);
  };
}