Not able to resolve reporters when running in gulp

[benedictchen]

None of the reporters are able to be resolved.

return gulp.src(allTestFiles, { read: false })
        .pipe(mocha({
          includeUntested: true,
          nyc: true,
          istanbul: true,
          bin: isparta,
          reporter: [
            'html',
            'lcov',
          ],
          produceSourceMap: true,
          sourceMap: true,
          instrument: true,
          require: [
            'source-map-support/register',
            'babel-core/register',
          ],
        }))
        .on('end', done);

Error:

/node_modules/mocha/lib/mocha.js:193
      throw new Error('invalid reporter "' + reporter + '"');
      ^

Error: invalid reporter "lcov"