old_contents: var changed = require('gulp-changed'),
  	gulp = require('gulp'),
  	log = require('gulp-pd-log'),
  	sass = require('gulp-sass'),
  	watch = require('gulp-watch'),
  	minifyCss = require('gulp-minify-css'),
  	uglify = require('gulp-uglify'),
  	concat = require('gulp-concat'),
  	wrap = require('gulp-wrap'),
  
  	sassSrc = 'view/**/*.scss',
  	sassDest = 'view',
  	jsSrc = [
  		'view/js/services/negative-undo.js',
  		'view/js/controllers/negative-frame.js',
  		'view/js/controllers/negative-tabs.js',
  		'view/js/negative.js'
  	],
  	jsDest = 'view';
  
  gulp.task('sass', function () {
  	return gulp.src(sassSrc)
  		.pipe(sass())
  		.pipe(minifyCss())
  		.pipe(changed(sassDest, {
  			hasChanged: changed.compareSha1Digest
  		}))
  		.pipe(gulp.dest(sassDest));
  });
  
  gulp.task('js', function () {
  	return gulp.src(jsSrc)
  		.pipe(concat('index.js'))
  		.pipe(wrap("(function (window, document, JSON) { \n\n'use strict';\n\n<%= contents %>\n})(window, document, JSON);"))
  		.pipe(changed(sassDest, {
  			hasChanged: changed.compareSha1Digest
  		}))
  		.pipe(gulp.dest(jsDest));
  });
  
  
  gulp.task('watch', function () {
  	watch(sassSrc, function () {
  		gulp.start('sass');
  	});
  	watch(jsSrc, function () {
  		gulp.start('js')
  	});
  });
  
  gulp.task('default', [ 'js', 'sass', 'watch' ]);
  
new_contents: var changed = require('gulp-changed'),
  	gulp = require('gulp'),
  	sass = require('gulp-sass'),
  	watch = require('gulp-watch'),
  	minifyCss = require('gulp-minify-css'),
  	concat = require('gulp-concat'),
  	wrap = require('gulp-wrap'),
  
  	sassSrc = 'view/**/*.scss',
  	sassDest = 'view',
  	jsSrc = [
  		'view/js/services/negative-undo.js',
  		'view/js/controllers/negative-frame.js',
  		'view/js/controllers/negative-tabs.js',
  		'view/js/negative.js'
  	],
  	jsDest = 'view';
  
  gulp.task('sass', function () {
  	return gulp.src(sassSrc)
  		.pipe(sass())
  		.pipe(minifyCss())
  		.pipe(changed(sassDest, {
  			hasChanged: changed.compareSha1Digest
  		}))
  		.pipe(gulp.dest(sassDest));
  });
  
  gulp.task('js', function () {
  	return gulp.src(jsSrc)
  		.pipe(concat('index.js'))
  		.pipe(wrap("(function (window, document, JSON) { \n\n'use strict';\n\n<%= contents %>\n})(window, document, JSON);"))
  		.pipe(changed(sassDest, {
  			hasChanged: changed.compareSha1Digest
  		}))
  		.pipe(gulp.dest(jsDest));
  });
  
  
  gulp.task('watch', function () {
  	watch(sassSrc, function () {
  		gulp.start('sass');
  	});
  	watch(jsSrc, function () {
  		gulp.start('js')
  	});
  });
  
  gulp.task('default', [ 'js', 'sass', 'watch' ]);
  
subject: Remove unused modules from gulpfile