gistfile1.txt

import gulp from 'gulp';
import del from 'del';
import babel from 'gulp-babel';
import mocha from 'gulp-mocha';
import help from 'gulp-task-listing';
import eslint from 'gulp-eslint';
import sourcemaps from 'gulp-sourcemaps';

const config = {
  paths: {
    js: {
      src: 'src/**/*.js', // javascript source files
      dist: 'dist/' // destination for compiled source
    },
    test: {
      src: 'test/**/*.js', // test case source files
      dist: 'test-dist/', // destination for compiled source
      run: 'test-dist/*.js' // destination to run tests
    }
  }
};

const options = {
  presets: ['es2015'],
  plugins: ['transform-runtime', 'syntax-async-functions', 'transform-async-to-generator'] // include ES7 async
};

gulp.task('help', help);

// lint the source files and then build them. Doest not include test cases
gulp.task('build', ['lint', 'build-src']);

// build source files
gulp.task('build-src', () =>
  gulp.src(config.paths.js.src)
    .pipe(sourcemaps.init()) // can sometimes be buggy
    .pipe(babel(options))
    .pipe(sourcemaps.write('.'))
    .pipe(gulp.dest(config.paths.js.dist))
);

// build test cases
gulp.task('build-test', () =>
  gulp.src(config.paths.test.src)
    .pipe(sourcemaps.init())
    .pipe(babel(options))
    .pipe(sourcemaps.write('.'))
    .pipe(gulp.dest(config.paths.test.dist))
);

// watches over all source files (source and test)
gulp.task('watch', () => {
  gulp.watch(config.paths.js.src, ['build-src', 'test']);
  // do not require since we are using ava and it allows for pre-required files
  // we are using babal-register before it
  // gulp.watch(config.paths.test.src, ['build-test', 'test']);
});

// Run tests with mocha
gulp.task('test', () =>
  gulp.src([config.paths.test.run])
    .pipe(mocha({ reporter: 'spec' }))
    .on('error', (err) => console.log(err.stack))
);

// Runs linter 
gulp.task('lint', () =>
  gulp.src([
    'gulpfile.js',
    config.paths.test.src,
    config.paths.js.src
  ])
  .pipe(eslint())
  .pipe(eslint.format())
  .pipe(eslint.failAfterError())
);

// Clean up destination directories for compiled source
gulp.task('clean', () => del([config.paths.js.dist + '**', config.paths.test.dist + '**']));

// Default Task
gulp.task('default', ['lint', 'build', 'test']);