gulpfile.js

var gulp = require('gulp'),
    fs = require('fs'),
    header = require('gulp-header'),
    coffee = require('gulp-coffee'),
    replace = require('gulp-replace'),
    uglify = require('gulp-uglify'),
    coffeelint = require('gulp-coffeelint'),
    minifyCSS = require('gulp-minify-css'),
    rename = require('gulp-rename'),
    gutil = require('gulp-util');

var path = {
    coffee: 'src/coffee/BttrLazyLoading.coffee',
    copyright: 'copyright',
    version: 'version',
    css: 'src/css/bttrlazyloading.css',
    build: 'dist/'
};

var name = {
    js: 'jquery.bttrlazyloading.js',
    jsmin: 'jquery.bttrlazyloading.min.js',
    css: 'bttrlazyloading.css',
    cssmin: 'bttrlazyloading.min.css'
};

var getVersion = function() {
    return fs.readFileSync(path.version);
};

var getCopyright = function() {
    return fs.readFileSync(path.copyright);
};

gulp.task('default', ['lint', 'coffee', 'css']);

// https://www.npmjs.org/package/gulp-coffeelint
gulp.task('lint', function() {
    gulp.src(path.coffee)
        .pipe(coffeelint())
        .pipe(coffeelint.reporter());
});

// https://www.npmjs.org/package/gulp-coffee
gulp.task('coffee', function() {
    return gulp.src(path.coffee)
        .pipe(replace('@@version', getVersion()))
        .pipe(coffee())
        .pipe(rename(name.js))
        .pipe(header(getCopyright(), {
            version: getVersion()
        }))
        .pipe(gulp.dest(path.build))
        .pipe(uglify())
        .pipe(rename(name.jsmin))
        .pipe(header(getCopyright(), {
            version: getVersion()
        }))
        .pipe(gulp.dest(path.build));
});

// https://www.npmjs.org/package/gulp-minify-css
gulp.task('css', function() {
    return gulp.src(path.css)
        .pipe(rename(name.css))
        .pipe(header(getCopyright(), {
            version: getVersion()
        }))
        .pipe(gulp.dest(path.build))
        .pipe(minifyCSS())
        .pipe(rename(name.cssmin))
        .pipe(header(getCopyright(), {
            version: getVersion()
        }))
        .pipe(gulp.dest(path.build));
});