Modular Gulp task builder.

gulpfile.js

/// <binding AfterBuild='build' />

var gulp = require('gulp'),
   bower = require('main-bower-files'),
   clean = require('gulp-clean'),
   less = require('gulp-less'),
   minifyCSS = require('gulp-minify-css'),
   rename = require('gulp-rename'),
   typescript = require('gulp-tsc'),
   uglify = require('gulp-uglify');

var config = {
	development: true,

	modules: [
		'cms',
		'site'
	],

	cms: {
		srcRoot: './CMS/',
		destRoot: './wwwroot/cms/',
		scripts: {
			src: 'App/*.ts',
			dest: 'app'
		},
		styles: {
			src: 'Styles/*.less',
			dest: 'css'
		}
	},

	site: {
		destRoot: './wwwroot',
		scripts: {
			src: './Scripts/*.ts',
			dest: 'app'
		},
		styles: {
			src: './Styles/*.less',
			dest: 'css'
		}
	},

	components: {
		src: './bower_components/',
		dest: './wwwroot/lib/'
	}
}

var buildTasks = ['copy-components'];
var cleanTasks = ['clean-components'];

// Bower Components
gulp.task('copy-components', ['clean-components'], function () {
	return gulp.src(bower(), { base: config.components.src }).pipe(gulp.dest(config.components.dest));
});

gulp.task('clean-components', function () {
	return gulp.src(config.components.dest, { read: false }).pipe(clean({ force: true }));
});

// Pipeline Builders

function ScriptsTaskBuilder(module) {
	var src = config[module].srcRoot + config[module].scripts.src;
	var dest = config[module].destRoot + config[module].scripts.dest;

	gulp.task(module + '-clean-scripts', function () {
		return gulp.src(dest, { read: false }).pipe(clean({ force: true }));
	});

	gulp.task(module + '-build-scripts', [module + '-clean-scripts'], function () {
		var stream = gulp.src(src)
		.pipe(typescript({
			sourceMap: config.development,
			emitError: false,
			outDir: dest
		}));

		if (!config.development)
			stream.pipe(uglify());

		return stream.pipe(gulp.dest(dest));
	});

	buildTasks.push(module + '-build-scripts');
	cleanTasks.push(module + '-clean-scripts');
}

function StylesTaskBuilder(module) {
	var src = config[module].srcRoot + config[module].styles.src;
	var dest = config[module].destRoot + config[module].styles.dest;

	gulp.task(module + '-clean-styles', function () {
		return gulp.src(dest, { read: false }).pipe(clean({ force: true }));
	});

	gulp.task(module + '-build-styles', [module + '-clean-styles'], function () {
		var stream = gulp.src(src)
		.pipe(less());

		if (!config.development)
			stream.pipe(minifyCSS({ compatibility: 'ie8' }));

		return stream.pipe(gulp.dest(dest));
	});

	buildTasks.push(module + '-build-styles');
	cleanTasks.push(module + '-clean-styles');
}

// Tasks

for (var i in config.modules) {
	ScriptsTaskBuilder(config.modules[i]);
	StylesTaskBuilder(config.modules[i]);
}

gulp.task('build', buildTasks, function () {
	// Add custom build logic here:

});

gulp.task('clean', cleanTasks, function () {
	// Add custom clean logic here:

});