9.1.0 • Public • Published

    gulp-build-fozzie 🐻

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    Gulp build tasks for use across Fozzie modules.



    First, add gulp and gulp-build-fozzie as dependencies

    yarn add gulp @justeat/gulp-build-fozzie

    Next, inside your gulpfile.js, require the build function from @justeat/gulp-build-fozzie, then pass gulp as the first argument.

    const gulp = require('gulp');
    const { build } = require('@justeat/gulp-build-fozzie');
    build(gulp, /*options*/);

    You can optionally pass in options which will override the default config values.

    That's it! You can now run any of the Gulp tasks.

    Optional setup

    Transpile es2015 code

    To ensure that the scripts:bundle task can transpile es2015 code, add a .babelrc file, with the @babel/preset-env preset, to the root of your project:

        "presets": ["@babel/preset-env"]

    If you do not add a .babelrc file (you may be writing es5 code for example) then the code will be bundled up as is.

    JavaScript Linting

    Add an .eslintrc file to the root of your project with the following content to use the JS linting rules we recommend when running the scripts:lint task:

        "extends": "@justeat/eslint-config-fozzie"

    If you wish to extend or override these rules you can simply add them after the extends line in the .eslintrc file.

    For more information on how you can configure eslint check out the documentation.

    N.b. You may also find that you get an error when adding eslint which reads Parsing error: Cannot read property 'ecmaFeatures' of undefined. If you see this message, then add this to your package.json followed by running yarn install:

    "resolutions": {
      "espree": "3.5.4"

    This is a temporary fix dependent on the progress of this issue open on ESLint.

    CSS Linting

    To use our recommended fozzie stylelint linting rules add the following into your package.json file:

    "stylelint": {
        "extends": "@justeat/stylelint-config-fozzie"

    If you wish to extend or override these rules you can simply add them after the extends line in the package.json file.

    For more information on how you can configure stylelint check out the documentation.

    Config and pathBuilder

    You can also access the config and pathBuilder objects which are used inside of gulp-build-fozzie by requiring them:

    const { config, pathBuilder } = require('@justeat/gulp-build-fozzie');

    These are exposed for convenience, and means that you do not need to manually build paths and maintain a separate config object for any custom tasks in your project. It also reduces duplication and prevents bugs which can arise from specifying incorrect paths.

    config object

    This is the config object which is used inside of gulp-build-fozzie, if you have passed any options via the build method they will be available here.

    See the Options section below for the details of this object.

    pathBuilder object

    The pathBuilder object is used inside of gulp-build-fozzie in order to build the paths used in the gulp tasks.

    See the Path Builder section below for details on which paths are available.

    The Gulp Tasks


    Runs the following tasks

    • scss:lint

      Lint all SCSS files in the source directory — this runs before the css:bundle task.

      This task will also automatically fix any errors that it can (through stylelint's autofix setting).

    • css:lint

      Lint all CSS files in the dist directory — this runs after the css:bundle task.

    • clean:css

      Removes any CSS already in the dist directory.

    • css:bundle

      Performs a variety of tasks including;

      • Makes environment variables available to Sass
      • Pull in Eyeglass modules
      • Run postcss plugins
      • Minify the CSS
      • Add hashed version to file name
      • Output bundle to the dist directory


    Runs the following tasks

    • scripts:lint

      Lint all JavaScript in the source directory. This task will also attempt to automatically fix any rules via the ESLint --fix flag.

    • scripts:test

      Runs any unit tests found in the JavaScript source directory using Jest.

    • scripts:test:coverage

      Runs the JS unit tests and display a coverage report once complete.

    • clean:scripts

      Removes any JavaScript already in the dist directory.

    • scripts:bundle

      Performs a variety of tasks including;

      • ES2015 transpilation using Babel
      • Bundle all code into a single file
      • Generate sourcemap files
      • Minify the JavaScript
      • Add hashed version to file name
      • Output bundle to the dist directory


    Adds the server-side file required for the errorLogger to be inserted into the filesystem.


    Runs the following tasks

    • clean:images

      Removes any images already in the dist directory.

    • images:optimise

      Optimises all images found in the source directory then copies them to the dist directory.

    • images:svg-sprite

      Generate an SVG sprite and copy into the dist directory

    It also runs the copy:img and copy:assets tasks.


    Runs the following tasks

    • service-worker:locate

    Discovers scripts in the service worker directory.

    • service-worker:copy

    Copies the worker's internal scripts to the dist directory.

    • service-worker:write

    Generates a service worker to pre-cache the assets defined in the config.

    copy:js, copy:css, copy:img, copy:fonts & copy:docs

    Each of these tasks copies the specified set of assets from the src to the dist asset folders.

    See the config section for details on how to configure these tasks.


    Runs the default task then the following watch tasks.

    • watch:css

    Runs the css task when a CSS file is changed.

    • watch:scripts

    Runs the scripts task when a JavaScript file is changed.

    • watch:scripts:test

    Runs the scripts:lint and scripts:test tasks when a JavaScript unit test file is changed.

    • watch:images

    Runs the images task when an image file is changed.


    Runs the same tasks as watch as well as the following watch tasks.

    • watch:docs:templates

    Runs the assemble task when documentation files are changed.

    Development-only tasks

    • docs

    Builds a fresh copy of any documentation found in the config.docs.rootDir directory using Assemble, then watches for any file changes and reloads the web page when changes are detected in the config.docs.distDir directory.

    • docs:deploy

    Builds the documentation and then pushes the dist directory to the gh-pages branch.

    • docs:release

    Pushes the documentation dist directory to the gh-pages branch.

    • clean:docs

    Removes document files already in the docs dist directory.

    • copy:img:docs

    Copies all of the images in the assets dist folder over to the docs dist folder.

    • browser-sync

    Watches for changes to files and reloads a local website instance.

    • browser-sync:docs

    Generates the documentation files then opens the docs in a local server.

    • assemble

    Generates the documentation files.


    Here is the outline of the configuration options, descriptions of each are below.

        css: {
        js: {
            files: {
                main: {
        logger: {
        img: {
        importedAssets: {
        sw: {
        copy: {
        docs: {
        fonts: {
        browserSync: {
        misc: {
        gulp: {


    Type: string

    Default: '.'

    The root directory of your website.


    Type: string

    Default: 'src'

    Root source directory for your assets.


    Type: string

    Default: 'dist'

    Root dist directory for your assets.


    Type: boolean

    Default: true

    Will add a content hash to the JS and CSS filenames, generating a new filename if any of the file's contents have changed. This can be utilised to force the clients to get the latest version of an updated asset.


    Type: String

    Returns the current package version.


    • scssDir

      Type: string

      Default: 'scss'

      The directory where your SCSS files reside.

    • cssDir

      Type: string

      Default: 'css'

      The bundled CSS file will be output to this directory.

    • lintPaths

      Type: array

      Default: ['']

      Allows additional paths to be included or excluded from the linting task.

      By default, the task will lint all .scss files within the scssDir directory.

    • sourcemaps

      Type: boolean

      Default: isDev

      Turns sourcemaps on or off.

    • usePackageVersion

      Type: boolean

      Default: false

      When set to true this will bundle a versioned css file e.g 'filename-[version].css'.


    • files

      Type: Object


          main: {
              srcPath: 'index.js',
              distFile: 'script.js'

      An Object, that takes one or more child objects each describing a JavaScript bundle entry point and destination. Each of these objects can have the following properties:

      • srcPath

        Type: string

        Default: 'index.js'

        The file path to a bundle entry point in your JavaScript.

      • distFile

        Type: string

        Default: 'script.js'

        The filename for the JavaScript bundle once compiled.

    • jsDir

      Type: string

      Default: 'js'

      Name of the directory where all of your JavaScript files are kept.

      Compiled JavaScript files will be placed inside a directory with the same name.

    • lintPaths

      Type: array

      Default: ['']

      Allows additional paths to be included or excluded from the JS linting task.

      By default, the task will lint all files within the jsDir directory.

    • usePackageVersion

      Type: boolean

      Default: false

      When set to true this will bundle a versioned JS file e.g 'filename-[version].js'.

    • stripDebug

      Type: boolean

      Default: true

      This can also be controlled using the --noStripDebug flag. When this flag is added, console.log() statements will not be removed for production builds.


      gulp scripts:bundle --prod --noStripDebug

      This would generate the JS files as part of a production build, but would still include console.log() statements. Intended for QA releases.

      gulp scripts:bundle --prod

      This is a normal production build and would not include console.log() statements.

      gulp scripts:bundle --noStripDebug

      For non-production builds, the flag has no effect: you will still get debug statements even if include the flag.


    • dir

      Type: string

      Default: 'js/shared'

      Name of the directory where your js error logger file will live.

    • file

      Type: string

      Default: 'js-error.js'

      Name of the error logger file.


    • imgDir

      Type: string

      Default: 'img'

      Name of the directory where your image files are kept.

      Processed image files will be placed inside a directory with the same name.

    • svgSpriteFilename

      Type: string

      Default: 'sprite.svg'

      Filename of the SVG sprite which is generated from any SVG assets found in the image directory.


    • importedAssetsSrcGlob

      Type: string

      Default: 'node_modules/@justeat/*/'

      Glob of packages containing assets to be copied to assetDistDir.

    • verbose

      Type: boolean

      Default: 'true'

      Whether to log the names of all assets being copied. Passed on to f-copy-assets.


    • isEnabled

      Type: boolean

      Default: false

      Determines whether the service worker is generated or not.

    • swDir

      Type: string

      Default: 'sw'

      Name of the directory where your service worker's custom internal scripts are kept in.

      Scripts here will be placed inside a directory with the same name.

    • outputFile

      Type: string

      Default: 'service-worker.js'

      The name of the generated service worker file, to be placed in the root of your application.

    • staticFileGlobs

      Type: array

      Default: []

      The static files in your application to be cached by the service worker.

    • dynamicFileRegex

      Type: array

      Default: []

      An array of regex to match the dynamic content or API calls to cache e.g. [/^https:\/\/example\.com\/api/, /^https:\/\/fonts.googleapis.com\/css/].

    • dynamicFileStrategy

      Type: string

      Default: cacheFirst

      The cache strategy to be used for content matched by dynamicFileRegex - these correspond to the sw-toolbox handlers.

    • importScripts

      Type: array

      Default: []

      Any additional internal scripts to include, aside from those in swDir.

    • cacheId

      Type: string

      Default: ''

      An optional string used to differentiate caches on the same origin during local development.


    • js, css img, fonts & docs

      Type: Object

      Default: {}

      copy.js, copy.css, copy.img, copy.fonts and copy.docs each take an object list of assets in the format:

          js: {
            prism: {
                path: '/libs/**/*',
                dest: '/libs',
                revision: false

      In which:

      • path is a string specifying the path within the relevant asset src folder of the asset to be copied.
      • dest is a string specifying that destination folder for the asset to be copied to, within the relevant asset dist folder.
      • revision is a boolean such that if it is true, the asset will be revision hashed when copied to its destination.

      path and dest must always be defined for each asset you wish to copy (except for copy:docs which uses the root docsDist path for the dest).

      The object key (which in the above example is prism) of each asset is simply for your own use to identify each asset in your config.

    • copy:assets

      Copies assets from packages to the dist directory.


    • rootDir

      Type: string

      Default: './docs'

      Root directory where your documentation files reside.

      By default your source files will be searched for in docs/src, and the generated content will be output to docs/dist.

    • srcDir

      Type: string

      Default: 'src'

      The source directory for your documentation template files.

      By default the documentation task will use the path docs/src – with the src part of this path controlled by this config variable.

    • distDir

      Type: string

      Default: 'dist'

      The directory your documentation will be compiled to.

      By default the documentation task will use docs/dist – with the dist part of this path controlled by this config variable.

    • assetDir

      Type: string

      Default: 'assets/'

      The directory your generated assets will be placed inside the documentation directory.

      By default the documentation task will use docs/dist/assets/ – with the assets/ part of this path controlled by this config variable.

    • templDir

      Type: string

      Default: 'templates'

      The name of the directory where your documentation template files are kept.

    • dataDir

      Type: string

      Default: 'data'

      The name of the directory where your documentation data files are kept.

    • outputAssets

      Type: boolean

      Default: false

      Indicates whether or not the JavaScript, CSS and image files should be placed into the docs/dist/assets/ directory.

    • remoteBase

      Type: string

      Default: ''

      Applies a base path to asset URLs when publishing documentation to Github pages. By default this is set to be an empty string.

    • helpers

      Type: object

      Default: {}

      Can pass in an object set of functions, which will be exposed in handlebars as helper functions in the documentation tasks when called using their object key.

      For example:

        'toLowercase': (input) => { return input.toLowerCase(); }

      Will expose the helper toLowercase so that using {{toLowercase name}} within a handlebars template will convert the handlebars string name to lowercase.

    • excludeTemplateDirs

      Type: array

      Default: ['resources']

      Directory names which should be ignored when adding any shared templates to the documentation. By default the array contains known directory names which should be ignored.


    • fontsDir

      Type: string

      Default: 'fonts'

      Name of the directory where your font files are kept.


    • files

      Type: array

      Default: []

      List of paths to watch for changes. Accepts globs.

    • proxy

      Type: string

      Default: ''

      URL of local website instance.

    • reloadDebounce

      Type: number

      Default: 1000

      Wait for a specified window of event-silence (in milliseconds) before sending any reload events.


    • showFileSize

      Type: boolean

      Default: true

      Should file sizes be displayed when a task is run?

    • showFiles

      Type: boolean

      Default: true

      Should file names be displayed when a task is run?


    • changeEvent

      Type: function

      Event which fires when a file is modified.

    • onError

      Type: function

      Event which fires when an error occurs.

    Other config

    The following options are also present in the config but cannot be overridden.

    • isProduction

      Type: boolean

      Set to true when the --prod flag is passed.

    • isDev

      Type: boolean

      Set to the opposite value of isProduction.

    • lintModules

      Type: boolean

      When set to true, by setting the --lintModules flag when running the build, the build will also lint SCSS files within sub-dependencies. This is intended to help with local development when using dependency linking.

    Path Builder

    You can access the pathBuilder paths like this.

    const { pathBuilder } = require('@justeat/gulp-build-fozzie');
    gulp.task('scss', () => gulp.src(`${pathBuilder.scssSrcDir}/**`)

    These are the paths which the pathBuilder object provides.


    • scssSrcDir

      Default: 'src/scss'

    • cssDistDir

      Default: 'dist/css'

    • jsSrcDir

      Default: 'src/js'

    • jsDistDir

      Default: 'dist/js'

    • imgSrcDir

      Default: 'src/img'

    • imgDistDir

      Default: 'dist/img'

    • importedAssetsDistDir

      Default: 'dist/imported-assets'

    • swOutputPath

      Default: '.'

    • swSrcDir

      Default: 'src/sw'

    • swDistDir

      Default: 'dist/sw'

    • docsSrcDir

      Default: './docs/src'

    • docsDistDir

      Default: './docs/dist'

    • docsTemplateDir

      Default: './docs/src/templates'

    • docsDataDir

      Default: './docs/src/data'

    • docsAssetsDistDir

      Default: './docs/dist/assets/'

    • docsCssDistDir

      Default: './docs/dist/assets/css'

    • docsJsDistDir

      Default: './docs/dist/assets/js'

    • docsImgDistDir

      Default: './docs/dist/assets/img'

    • fontsSrcDir

      Default: 'src/fonts'

    • fontsDistDir

      Default: 'dist/fonts'

    Running the unit tests

    To run the unit tests for the project run the yarn test script. To see the test coverage run the test:cover script.




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