Gulp Configurable Tasks

gulp-config.json

{
    "theme": "default",
    "minifyCss": true,
    "uglifyJS": true,
    "bless" : {
        "useImport": false
    },    
    "bootstrap": {
        "js": [
            "bower_components/bootstrap/js/transition.js",
            "bower_components/bootstrap/js/collapse.js",
            "bower_components/bootstrap/js/carousel.js",
            "bower_components/bootstrap/js/dropdown.js",
            "bower_components/bootstrap/js/modal.js",
            "bower_components/bootstrap/js/tab.js"
        ]
    },
    "modernizr": {
        "detectors": [
            "bower_components/modernizr/feature-detects/css-filters.js",
            "bower_components/modernizr/feature-detects/forms-formattribute.js"
        ]
    },
    "customJsPaths": [],
    "htmlSrc": ["src/**"]
}

gulp.js

var config       = require('./gulp-config.json');

var gulp         = require('gulp'),
    less         = require('gulp-less'),
    minifycss    = require('gulp-minify-css'),
    bless        = require('gulp-bless'),
    jshint       = require('gulp-jshint'),
    concat       = require('gulp-concat'),
    uglify       = require('gulp-uglify'),
    util         = require('gulp-util'),
    notify       = require('gulp-notify'),
    rimraf       = require('gulp-rimraf'),
    fileinclude  = require('gulp-file-include');

var oPath        = {
    basePath: "../",
    defaultTheme: "default/",
    parts: {
        less: "less/style.less",
        js: "js/*.js",
        dist: "compiled/"
    }
};

/**
 * custom reporter for notify
 */
var customNotify = notify.withReporter(function (options, callback) {
    callback();
});

/**
 * method to deliver correct file paths to tasks
 * according to path object oPath
 *
 * @param {string} part - choose between less, js and dist
 * @return {array}
 */
var getPath = function (part) {
    var theme = (config.theme !== '') ? config.theme : oPath.defaultTheme;

    // for part js we have to return custom theme and default theme folder
    if(config.theme !== '' && part === 'js') {
        var aPaths = [
            oPath.basePath + theme + '/' + oPath.parts[part],
            oPath.basePath + oPath.defaultTheme + oPath.parts[part]
        ];
        config.customJsPaths.forEach(function(sPath) {
            aPaths.push(sPath);
        });
        return aPaths;
    }

    return [oPath.basePath + theme + '/' + oPath.parts[part]];
};

// LINT
gulp.task('lint', ['clean'], function() {
    return gulp.src(getPath('js'))
        .pipe(jshint())
        .pipe(jshint.reporter('default'));
});

// LESS
gulp.task('less', ['clean'], function() {
    var stream = gulp.src(getPath('less'))
        .pipe(less().on('error', customNotify.onError(function (error) {
            return 'Error compiling LESS: ' + error.message;
        })))
        .pipe(gulp.dest(getPath('dist') + 'css'));

    // this if statement is not nice yet and should be improved
    // if we do bless in the return part it proccs and error
    if (config.minifyCss === true) {
        stream
            .pipe(minifycss())
            .pipe(bless({
                imports: config.bless.useImport
            }))
            .pipe(gulp.dest(getPath('dist') + 'css'));
    } else {
        stream
            .pipe(bless({
                imports: config.bless.useImport
            }))
            .pipe(gulp.dest(getPath('dist') + 'css'));
    }

    return stream
        .pipe(gulp.dest(getPath('dist') + 'css'))
        .pipe(customNotify({
            message: 'Successfully compiled LESS'
        }));
});

// JavaScript
gulp.task('js', ['clean'], function() {
    var stream = gulp.src(getPath('js'))
        .pipe(concat('script.js'))
        .pipe(gulp.dest(getPath('dist') + 'js'));

    if (config.uglifyJS === true) {
        stream.pipe(uglify());
    }

    return stream
        .pipe(gulp.dest(getPath('dist') + 'js'))
        .pipe(customNotify({
            message: 'Successfully compiled JavaScript'
        }));
});

// Bootstrap JavaScript
gulp.task('bootstrapJs', ['clean'], function() {
    return gulp.src(config.bootstrap.js)
        .pipe(concat('bootstrap.min.js'))
        .pipe(uglify())
        .pipe(gulp.dest(getPath('dist') + 'js/bootstrap'))
        .pipe(customNotify({
            message: 'Successfully compiled Bootstrap JS'
        }));
});

// modernizr
var modernizrModules = ['bower_components/modernizr/modernizr.js'];
gulp.task('modernizr', ['clean'], function () {
    gulp.src(modernizrModules.concat(config.modernizr.detectors))
        .pipe(concat('modernizr.min.js'))
        .pipe(uglify())
        .pipe(gulp.dest(getPath('dist') + 'js/modernizr'))
        .pipe(customNotify({
            message: 'Successfully compiled Modernizr JS'
        }));
});

// Bootstrap Fonts
gulp.task('bootstrapFonts', ['clean'], function(){
    gulp.src('bower_components/bootstrap/fonts/*')
        .pipe(gulp.dest(getPath('dist') + 'fonts/'));

    gulp.src('bower_components/font-awesome/fonts/*')
        .pipe(gulp.dest(getPath('dist') + 'fonts/'));
});

// Fileinclude
gulp.task('fileinclude', function() {
    gulp.src(config.htmlSrc)
        .pipe(fileinclude({
            prefix: '@@',
            basepath: '@file'
        }))
        .pipe(gulp.dest('./'));
});

// Task section:
// --------------------------------------

// Clean always has to clean the "dist/" folder
gulp.task('clean', function() {
    var theme     = (config.theme !== '') ? config.theme : oPath.defaultTheme;
    var cleanPath = [oPath.basePath + theme + '/' + 'dist/'];

    if (typeof util.env.mode !== undefined && util.env.mode === 'dev') {
        cleanPath = [
            oPath.basePath + theme + '/' + 'dist/js/*.js',
            oPath.basePath + theme + '/' + 'dist/css/'
        ];
    }

    return  gulp.src(
                cleanPath,
                {read: false}
            )
            .pipe(rimraf({force: true}));
});

// Watch, use "--mode dev" to run in dev mode
gulp.task('watch', function() {
    gulp.watch(['less/**/*.less', getPath('js')], ['default']);
});

// Default task, use "--mode dev" to run in dev mode
gulp.task('default', function () {
    if (typeof util.env.mode !== undefined && util.env.mode === 'dev') {
        oPath.parts.dist = 'dist/';
    }
    // run default tasks
    gulp.start('bootstrapFonts', 'bootstrapJs', 'less', 'lint', 'js', 'modernizr');
});