gulpfile.babel.js

import gulp     from 'gulp';
import babel    from 'gulp-babel';
import del      from 'del';
import jasmine  from 'gulp-jasmine';
import istanbul from 'gulp-istanbul';
import reqDir   from 'require-dir';

import {
  build as config
} from './package.json';

import {
  Instrumenter as isparta
} from 'isparta';

gulp.task('clean', () => {
  return del([config.paths.dist, config.paths.coverage], { force: true });
});

function test() {
  return gulp.src(`${config.paths.spec}/**/*.js`)
    .pipe(jasmine());
}
gulp.task(test);

gulp.task('compile', () => {
  return gulp.src(`${config.paths.src}/**/*.js`)
    .pipe(babel())
    .pipe(gulp.dest(config.paths.dist));
});

gulp.task('build',   gulp.series('clean', 'test', 'compile'));
gulp.task('default', gulp.task('build'));

gulp.task('watch', () => {
  return gulp.watch([config.paths.src, config.paths.spec], gulp.task('build'));
});

const coverage = {
  setup() {
    return gulp.src(`${config.paths.src}/**/*.js`)
      .pipe(istanbul({
        instrumenter:    isparta,
        includeUntested: true
      }))
      .pipe(istanbul.hookRequire());
  },

  run() {
    return test()
      .pipe(istanbul.writeReports({
        reporters:  ['lcov', 'text'],
        reportOpts: { dir: config.paths.coverage }
      }));
  }
};
gulp.task('coverage', gulp.series(coverage.setup, coverage.run));

try {
  reqDir(config.paths.build);
} catch(err) {}