// main.js

import { extend } from './extend.js';

function Foo() {}
function Bar() {}
extend(Foo, Bar, {});
const baz = 5;
export default baz;

// extend.js

export function extend(parent, child, props) {
  child.__proto__ = parent;
  var proto = child.prototype = Object.create(parent.prototype);
  proto.constructor = child;
  for (var p in props)
    proto[p] = props[p];
}

// output

var baz = (function () {
  'use strict';

  function extend(parent, child, props) {
    child.__proto__ = parent;
    var proto = child.prototype = Object.create(parent.prototype);
    proto.constructor = child;
    for (var p in props)
      proto[p] = props[p];
  }

  function Foo() {}

  function Bar() {}

  extend(Foo, Bar, {});

  const baz = 5;

  return baz;

}());

// expected

var baz = (function () {
  'use strict';

  const baz = 5;

  return baz;
}());