2.js

var foo = "foo1";

const ctx = {
  func: variable => {
    console.log(variable);
  },
  foo: "f1"
};

function veryPoorSandbox(code, ctx) {
  with (ctx) {
    eval(code);
  }
}

const code = `func(foo)`;
veryPoorSandbox(code, ctx); 

// f1