stockoverflow multiple gulp watch question code

gistfile1.js

var gulp = require('gulp');
var gutil = require('gulp-util');
var bower = require('bower');
var concat = require('gulp-concat');
var sass = require('gulp-sass');
var minifyCss = require('gulp-minify-css');
var rename = require('gulp-rename');
var sh = require('shelljs');

var templateCache = require('gulp-angular-templatecache');
var inject = require('gulp-inject');
var watch = require('gulp-watch');
var batch = require('gulp-batch');
var plumber = require('gulp-plumber');

var paths = {
    sass: ['./scss/**/*.scss'],
    templates: ['./www/modules/**/*.html'],
    scripts: [
        './www/js/templates.build.js',
        './www/modules/app.js',
        './www/modules/**/*.js'
    ],
};

gulp.task('default', ['sass']);

gulp.task('templates', function(done) {
    gulp.src(paths.templates)
        .pipe(templateCache('templates.build.js', {
            standalone: true,
            base: function(file) {
                // keep only file name
                return file.history[0].match(/\/([^\/]+$)/)[1];
            }
        }))
        .pipe(gulp.dest('./www/js/'))
        .on('end', done);
});

gulp.task('inject', function() {
    var target = gulp.src('./www/index.html');
    var sources = gulp.src(paths.scripts, {
        read: false
    });

    return target.pipe(inject(sources, {
        relative : true
    }))
        .pipe(gulp.dest('./www'));
});

gulp.task('sass', function(done) {
    gulp.src('./scss/ionic.app.scss')
        .pipe(plumber(function (error) {
            gutil.log(gutil.colors.red(error.message));
            this.emit('end', done);
        }))
        .pipe(sass({
            sourceComments: 'map'
        }))
        .pipe(gulp.dest('./www/css/'))
        .pipe(minifyCss({
            keepSpecialComments: 0
        }))
        .pipe(rename({
            extname: '.min.css'
        }))
        .pipe(gulp.dest('./www/css/'))
        .on('end', done);
});


gulp.task('watch', function () {
    watch(paths.sass, batch(function (done) {
        gulp.start('sass');
        done();
    }));

    watch(paths.templates, batch(function (done) {
        gulp.start('templates');
        done();
    }));

    watch(paths.scripts, batch(function (done) {
        gulp.start('inject');
        done();
    }));
});