export default class is not working

[dcleao]

I am trying to compile a file with the following content:

export default class Foo {}

The output of the compilation is:

"use strict";

define(["@babel/runtime/helpers/classCallCheck"], function (_classCallCheck) {
  var Foo = function Foo() {
    _classCallCheck(this, Foo);
  };

  export { Foo as default };
});

My babel configuration is:

{
  "presets": [
    [
      "@babel/preset-env",
      {
        "useBuiltIns": "usage",
        "debug": false,
        "corejs": 3,
        "targets": {
          "ie": "11",
          "edge": "40",
          "safari": "10",
          "firefox": "58",
          "chrome": "64"
        }
      }
    ]
  ],
  "plugins": [
    "@babel/plugin-transform-runtime",
    "babel-plugin-transform-es2015-modules-simple-amd"
  ],
  "sourceType": "module",
  "minified": false
}

And the versions of all of these, as declared in package.json are:

    "@babel/cli": "^7.6.0",
    "@babel/core": "^7.6.0",
    "@babel/plugin-transform-runtime": "^7.6.2",
    "@babel/preset-env": "^7.6.0",
    "babel-plugin-transform-es2015-modules-simple-amd": "^0.3.0",
    "core-js": "^3.2.1",

Do you know what might be causing this?