Gulp Stylus Browserify - added error handling for production. Need to work out errors for watchify task.

gulp watchify

var source = require('vinyl-source-stream'),
    watchify = require('watchify'),
    gulp = require('gulp'),
    fs = require('fs'),
    gulp = require('gulp'),
    browserify = require('gulp-browserify'),
    uglify = require('gulp-uglify'),
    ngmin = require('gulp-ngmin'),
    stylus = require('gulp-stylus'),
    livereload = require('gulp-livereload'),
    str2jsify = require('string-to-jsify'),
    minifyCSS = require('gulp-minify-css'),
    plumber = require('gulp-plumber'),
    gutil = require('gulp-util');
 

// = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = =
// Watching Functions - for updating css and JS
function watch_css(watch,src){
  gulp.watch(watch,function(){
    gulp.src(src)
      .pipe(stylus({use: ['nib'],set:['compress','include css']}))
      .pipe(gulp.dest('build/'))
      .pipe(livereload());
  });
}

function watch_watchify(src,outfile) {
  var bundler = watchify(src);
      bundler.transform(str2jsify.configure({extensions: '.html'}));
      bundler.transform('jadeify');
      bundler.transform('coffeeify');
      bundler.transform('deamdify');
      bundler.transform('debowerify');
      
      bundler.on('update', rebundle);
  function rebundle () {
    return bundler.bundle()
      .pipe(source(outfile))

      .pipe(gulp.dest('./build'))
      .pipe(livereload());
  }
  return rebundle();
}

//= = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = 
// production scripts below
function build_css(src){  
  gulp.src(src)
    .pipe(stylus({use: ['nib'],set:['compress','include css']}))
    .pipe(minifyCSS({keepSpecialComments:0}))
    .pipe(gulp.dest('./build/'));
};

//bundle all dev files into main.js not including common files
function build_browserify(src){
  gulp.src(src)
    .pipe(plumber())
    .pipe(browserify({
      debug : false,
      detectGlobals: false,
      transform: [str2jsify.configure({extensions: '.html'}),'jadeify','coffeeify','deamdify','debowerify'],
    }))
    .pipe(ngmin())
    .pipe(uglify({mangle:false}))//experiment changing this - as ngmin updates it may work more successfully
    .pipe(gulp.dest('./build/'))
    .on('error', gutil.log);
}

//= = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = 
//default task watches
gulp.task('default', function() {
  watch_watchify('./dev/main.js','main.js');//input path,output filename
  watch_css(['dev/**/*.styl','dev/**/*.css'],'dev/main.styl');//watch paths, input path
})

//production task builds, minifies etc...
gulp.task('production',function(){
  build_browserify('./dev/main.js');
  build_css('dev/main.styl');
  build_browserify('./toolbar/toolbar.js');
  build_css('toolbar/toolbar.styl');
});

Yes, that's right. Sorry for the very late response, didn't get notified of this message. I imagined you've worked that out by now. The only problem I've had with this task so far is error handling. Just had a quick mess with the gulp-plumber plugin, which gives meaningful errors on the production task, but still working out how to use it with watchify.