Wallaby with Browserify and TypeScript modules

I am trying to get Wallaby to work with a TypeScript app, using Browserify and Wallabify. However, when I run Wallaby, it outputs No failing tests, 0 passing, and all test indicators are grey.

The file app/spec.setup.ts is responsible for loading node modules dependencies such as chai, sinon, and the app's main module. app/spec.util.ts provides some helpers, imported by individual spec files.

module.exports = function() {
  var wallabify = require('wallabify');

  var wallabyPostprocessor = wallabify({
        entryPatterns: [
          'app/spec.setup.ts',
          'app/src/**/*.spec.ts'
        ]
      }
  );

  return {
    files: [
      {pattern: 'app/spec.setup.ts', load: false, instrument: false},
      {pattern: 'app/spec.util.ts', load: false, instrument: false},
      {pattern: 'app/src/**/*.ts', load: false},
      {pattern: 'app/src/**/*.spec.ts', ignore: true}
    ],

    tests: [
      {pattern: 'app/src/**/*.spec.ts', load: false}
    ],

    testFramework: 'mocha',

    postprocessor: wallabyPostprocessor,

    bootstrap: function (w) {
      // outputs test file names, with .ts extensions changed to .js
      console.log(w.tests);

      window.__moduleBundler.loadTests();
    }
  };
};

What's interesting is that I don't get any feedback from changing entryPatterns, even setting it to an empty array or invalid file names. The result is still the same. Only if I remove it entirely, I get errors such as Can't find variable: sinon.

I've also figured that the entryPatterns list may need the compiled file names, i.e. .js instead of .ts extension. However, when I do that, I get Postprocessor run failure: 'import' and 'export' may appear only with 'sourceType: module' on spec.setup.ts.

I don't know what is the correct way to configure Wallabify for TypeScript compilation, and I couldn't find any complete examples on the web, so I'd appreciate any hints.

P.S. with my current StackOverflow reputation I couldn't add two new tags: wallaby and wallabify. Could someone do me a favour and add the two tags please.