'use strict';

const watchify = require('watchify');
const browserify = require('browserify');
const gulp = require('gulp');
const source = require('vinyl-source-stream');
const buffer = require('vinyl-buffer');
const gutil = require('gulp-util');
const sourcemaps = require('gulp-sourcemaps');
const assign = require('lodash.assign');

// add custom browserify options here
const customOpts = {
  entries: ['./src/js/app.js'],
  debug: true
};
const opts = assign({}, watchify.args, customOpts);
const b = watchify(browserify(opts));

// add transformations here
// i.e. b.transform(coffeeify);

gulp.task('js', bundle); // so you can run `gulp js` to build the file
b.on('update', bundle); // on any dep update, runs the bundler
b.on('log', gutil.log); // output build logs to terminal

function bundle() {
  return b.bundle()
    // log errors if they happen
    .on('error', gutil.log.bind(gutil, 'Browserify Error'))
    .pipe(source('bundle.js'))
    // optional, remove if you don't need to buffer file contents
    .pipe(buffer())
    // optional, remove if you dont want sourcemaps
    .pipe(sourcemaps.init({loadMaps: true})) // loads map from browserify file
       // Add transformation tasks to the pipeline here.
    .pipe(sourcemaps.write('./')) // writes .map file
    .pipe(gulp.dest('./src'));
}