gulpfile.js

// ## Globals
var argv         = require('minimist')(process.argv.slice(2));
var autoprefixer = require('gulp-autoprefixer');
var browserSync  = require('browser-sync').create();
var critical     = require('critical');
var changed      = require('gulp-changed');
var concat       = require('gulp-concat');
var flatten      = require('gulp-flatten');
var gulp         = require('gulp');
var gulpif       = require('gulp-if');
var imagemin     = require('gulp-imagemin');
var eslint       = require('gulp-eslint');
var lazypipe     = require('lazypipe');
//var less         = require('gulp-less');
var merge        = require('merge-stream');
var cssNano      = require('gulp-cssnano');
var plumber      = require('gulp-plumber');
var rev          = require('gulp-rev');
var runSequence  = require('run-sequence');
var sass         = require('gulp-sass');
var sourcemaps   = require('gulp-sourcemaps');
var svgMin       = require('gulp-svgmin');
var svgStore     = require('gulp-svgstore');
var uglify       = require('gulp-uglify');

// See https://github.com/austinpray/asset-builder
var manifest = require('asset-builder')('./assets/manifest.json');

// `path` - Paths to base asset directories. With trailing slashes.
// - `path.source` - Path to the source files. Default: `assets/`
// - `path.dist` - Path to the build directory. Default: `dist/`
var path = manifest.paths;

// `config` - Store arbitrary configuration values here.
// var config = manifest.config || {};
// 2016-11-19 - commented out because it is unused

// `globs` - These ultimately end up in their respective `gulp.src`.
// - `globs.js` - Array of asset-builder JS dependency objects. Example:
//   ```
//   {type: 'js', name: 'main.js', globs: []}
//   ```
// - `globs.css` - Array of asset-builder CSS dependency objects. Example:
//   ```
//   {type: 'css', name: 'main.css', globs: []}
//   ```
// - `globs.fonts` - Array of font path globs.
// - `globs.images` - Array of image path globs.
// - `globs.bower` - Array of all the main Bower files.
var globs = manifest.globs;

// `project` - paths to first-party assets.
// - `project.js` - Array of first-party JS assets.
// - `project.css` - Array of first-party CSS assets.
var project = manifest.getProjectGlobs();

// CLI options
var enabled = {
  // Enable static asset revisioning when `--production`
  rev: argv.production,
  // Disable source maps when `--production`
  maps: !argv.production,
  // Fail styles task on error when `--production`
  failStyleTask: argv.production,
  // Fail due to ESLint warnings only when `--production`
  failESLint: argv.production,
  // Strip debug statments from javascript when `--production`
  stripJSDebug: argv.production
};

// Path to the compiled assets manifest in the dist directory
var revManifest = path.dist + 'assets.json';

// Error checking; produce an error rather than crashing.
var onError = function (err) {
	console.log(err.toString());
	this.emit('end');
};

// ## Reusable Pipelines
// See https://github.com/OverZealous/lazypipe

// ### CSS processing pipeline
// Example
// ```
// gulp.src(cssFiles)
//   .pipe(cssTasks('main.css')
//   .pipe(gulp.dest(path.dist + 'styles'))
// ```
var cssTasks = function(filename) {
  return lazypipe()
    .pipe(function() {
      return gulpif(!enabled.failStyleTask, plumber());
    })
    .pipe(function() {
      return gulpif(enabled.maps, sourcemaps.init());
    })
    // .pipe(function() {
    //   return gulpif('*.less', less());
    // })
    .pipe(function() {
      return gulpif('*.scss', sass({
        outputStyle: 'nested', // libsass doesn't support expanded yet
        precision: 10,
        includePaths: ['.'],
        errLogToConsole: !enabled.failStyleTask
      }));
    })
    .pipe(concat, filename)
    .pipe(autoprefixer, {
      browsers: [
        'last 2 versions',
        'android 4'
      ]
    })
    .pipe(cssNano, {
      safe: true
    })
    .pipe(function() {
      return gulpif(enabled.rev, rev());
    })
    .pipe(function() {
      return gulpif(enabled.maps, sourcemaps.write('.', {
        sourceRoot: 'assets/styles/'
      }));
    })();
};

// ### JS processing pipeline
// Example
// ```
// gulp.src(jsFiles)
//   .pipe(jsTasks('main.js')
//   .pipe(gulp.dest(path.dist + 'scripts'))
// ```
var jsTasks = function(filename) {
  return lazypipe()
    .pipe(function() {
      return gulpif(enabled.maps, sourcemaps.init());
    })
    .pipe(concat, filename)
    .pipe(uglify, {
      compress: {
        'drop_debugger': enabled.stripJSDebug
      }
    })
    .pipe(function() {
      return gulpif(enabled.rev, rev());
    })
    .pipe(function() {
      return gulpif(enabled.maps, sourcemaps.write('.', {
        sourceRoot: 'assets/scripts/'
      }));
    })();
};

// ### Write to rev manifest
// If there are any revved files then write them to the rev manifest.
// See https://github.com/sindresorhus/gulp-rev
var writeToManifest = function(directory) {
  return lazypipe()
    .pipe(gulp.dest, path.dist + directory)
    .pipe(browserSync.stream, {match: '**/*.{js,css}'})
    .pipe(rev.manifest, revManifest, {
      base: path.dist,
      merge: true
    })
    .pipe(gulp.dest, path.dist)();
};

// ## Gulp tasks
// Run `gulp -T` for a task summary

// ### Styles
// `gulp styles` - Compiles, combines, and optimizes Bower CSS and project CSS.
// By default this task will only log a warning if a precompiler error is
// raised. If the `--production` flag is set: this task will fail outright.
gulp.task('styles', ['wiredep'], function() {
  var merged = merge();
  manifest.forEachDependency('css', function(dep) {
    var cssTasksInstance = cssTasks(dep.name);
    if (!enabled.failStyleTask) {
      cssTasksInstance.on('error', function(err) {
        console.error(err.message);
        this.emit('end');
      });
    }
    merged.add(gulp.src(dep.globs, {base: 'styles'})
      .pipe(plumber({errorHandler: onError}))               
      .pipe(cssTasksInstance));
  });
  return merged
    .pipe(writeToManifest('styles'));
});

// ### Scripts
// `gulp scripts` - Runs ESLint then compiles, combines, and optimizes Bower JS
// and project JS.
gulp.task('scripts', ['lint'], function() {
  var merged = merge();
  manifest.forEachDependency('js', function(dep) {
    merged.add(
      gulp.src(dep.globs, {base: 'scripts'})
        .pipe(plumber({ errorHandler: onError }))
        .pipe(jsTasks(dep.name))
    );
  });
  return merged
    .pipe(writeToManifest('scripts'));
});

// ### Fonts
// `gulp fonts` - Grabs all the fonts and outputs them in a flattened directory
// structure. See: https://github.com/armed/gulp-flatten
gulp.task('fonts', function() {
  return gulp.src(globs.fonts)
    .pipe(flatten())
    .pipe(gulp.dest(path.dist + 'fonts'))
    .pipe(browserSync.stream());
});

// ### Images
// `gulp images` - Run lossless compression on all the images.
gulp.task('images', function() {
  return gulp.src(globs.images)
    .pipe(imagemin([
      imagemin.jpegtran({progressive: true}),
      imagemin.gifsicle({interlaced: true}),
      imagemin.svgo({plugins: [{removeUnknownsAndDefaults: false}, {cleanupIDs: false}]})
    ]))
    .pipe(gulp.dest(path.dist + 'images'))
    .pipe(browserSync.stream());
});

// ### Svg
// `gulp svg` - Minifies all svg files
gulp.task('svg', function() {
    return gulp.src(path.source + 'images/sprite/*.svg')
    .pipe(svgMin())
    .pipe(svgStore({
        inlineSvg: true
    }))
    .pipe(gulp.dest(path.dist + 'images/sprite'))
    .pipe(browserSync.stream());
});

// ### Critical and Rename
// 'gulp critical' - Add inline critical CSS to <head> for faster rendering
// Use in conjunction with LoadCSS
// http://github.com/addyosmani/critical-path-css-demo
gulp.task('copystyles', function () {
    return gulp.src(['dist/styles/main.css'])
        .pipe($.rename({
            basename: "site" // site.css
        }))
        .pipe(gulp.dest('dist/styles'));
});

gulp.task('critical', ['build', 'copystyles'], function () {
    critical.generate({
        inline: true,
        base: '.', // base directory
        src: 'index.html', // if source is different, change here
        //styleTarget: 'dist/styles/main.css',
        dest: 'index.html', // file used on production site
        width: 320, // viewport width for index.html
        height: 480, // viewport height for index.html
        minify: true
    });
});

// ### ESLint
// `gulp lint` - Lints configuration JSON and project JS.
gulp.task('lint', function() {
  return gulp.src([
    'gulpfile.js'
  ].concat(project.js))
    .pipe(eslint())
    .pipe(eslint.format())
    .pipe(gulpif(enabled.failESLint, eslint.failAfterError()));
});

// ### Clean
// `gulp clean` - Deletes the build folder entirely.
gulp.task('clean', require('del').bind(null, [path.dist]));

// ### Watch
// `gulp watch` - Use BrowserSync to proxy your dev server and synchronize code
// changes across devices. Specify the hostname of your dev server at
// `manifest.config.devUrl`. When a modification is made to an asset, run the
// build step for that asset and inject the changes into the page.
// See: http://www.browsersync.io
gulp.task('watch', function() {
  browserSync.init({
    files: ['*.html'],
    server: {
        baseDir: "./"
    }
    //files: ['{lib,templates}/**/*.php', '*.php'],
    //proxy: config.devUrl,
    //snippetOptions: {
    //  whitelist: ['/wp-admin/admin-ajax.php'],
    //  blacklist: ['/wp-admin/**']
    //}
  });
  gulp.watch([path.source + 'styles/**/*'], ['styles']);
  gulp.watch([path.source + 'scripts/**/*'], ['lint', 'scripts']);
  gulp.watch([path.source + 'fonts/**/*'], ['fonts']);
  gulp.watch([path.source + 'images/**/*'], ['images']);
  gulp.watch([path.source + 'images/sprite/**/*'], ['svg']);
  gulp.watch(['bower.json', 'assets/manifest.json'], ['build']);
});

// ### Build
// `gulp build` - Run all the build tasks but don't clean up beforehand.
// Generally you should be running `gulp` instead of `gulp build`.
gulp.task('build', function(callback) {
  runSequence('styles',
              'scripts',
              ['fonts', 'images', 'svg'],
              callback);
});

// ### Wiredep
// `gulp wiredep` - Automatically inject Less and Sass Bower dependencies. See
// https://github.com/taptapship/wiredep
gulp.task('wiredep', function() {
  var wiredep = require('wiredep').stream;
  return gulp.src(project.css)
    .pipe(wiredep())
    .pipe(changed(path.source + 'styles', {
      hasChanged: changed.compareSha1Digest
    }))
    .pipe(gulp.dest(path.source + 'styles'));
});

// ### Gulp
// `gulp` - Run a complete build. To compile for production run `gulp --production`.
gulp.task('default', ['clean'], function() {
  gulp.start('build');
});