Run typedoc over library public API files to generate HTML files from customised typedoc theme
The resulting files are not really useful on their own; they will be used later to generate demo app code
function generateTypedocDocs(typedocDocsDir) {
  const publicApiConfigFile = path.resolve(__dirname, '../src/ng5-slider/lib/public_api.json');
  const publicApiConfig = JSON.parse(fs.readFileSync(publicApiConfigFile, { encoding: 'utf8' }));

  const files = publicApiConfig.exports
    .map(exportDef => path.resolve(__dirname, `../src/ng5-slider/lib/${exportDef.file}.ts`));

  const themeDir = path.resolve(__dirname, '../typedoc-theme');

  // HACK: When Typedoc finda a README.md file, it uses it to generate content for the index page of documentation
  // This is not very helpful, as it repeats the same stuff that's already shown on Github and NPM
  // So instead, replace the README.md with our own file
  const apiDocsReadmeFile = path.resolve(__dirname, '../typedoc-theme/README.md');
  utils.copyReadmeMd(apiDocsReadmeFile);

  const app = new typedoc.Application({
    module: 'commonjs',
    target: 'es6',
    includeDeclarations: false,
    experimentalDecorators: true,
    excludeExternals: true,
    theme: themeDir
  });

  app.generateDocs(files, typedocDocsDir);

  // HACK: restore the README.md to original
  const mainReadmeFile = path.resolve(__dirname, '../README.md');
  utils.copyReadmeMd(mainReadmeFile);
}