Browserslist Check Bundle

This bundle parses .browserslistrc files for a config called modern. It then provides a php service and a twig method to compare the user-agent string against this config.

It uses a great, light and fast user agent parsing library by @donatj.

The goal is to determine whether the browser requesting a response is "modern" in relation to JavaScript and CSS functionality.

You can use it to serve different front-end builds and save precious bandwidth for modern browsers by serving less polyfills, vendor prefixes and whatever else is handled by the .broserslistrc.

Installing

composer require barthy-koeln/browserslist-check-bundle

Config

Your .browserslistrc file should look like this:

[modern]
Chrome >= 97
Edge >= 97
Firefox >= 91
Safari >= 14.1
Opera >= 82
iOS >= 14.5
Samsung >= 15
ChromeAndroid >= 100
FirefoxAndroid >= 98
Android >= 99

[legacy]
defaults
ie 11
safari >= 13
iOS >= 13

Important notes:

The [modern] config must be at the top
The constraints within that build must only map browser names with minimum versions using the >= operator. Browsers with versions higher or equal are "modern".

Caching The Browser Configuration

Your .browserslistrc file will be parsed and inlined as a PHP array when Symfony builds its cache.

Crawlers & Bots

This bundle recognizes a few evergreen crawlers capable of handling JavaScript and handles them as their browser counterpart (e.g. Chrome for Googlebot and Edge for Bingbot).

Simple Usage

<script src="/build/{{ is_modern_browser() ? 'modern' : 'legacy' }}.js" type="application/javascript"></script>

<?php

use BarthyKoeln\BrowserslistCheckBundle\DependencyInjection\BrowserslistCheck;

public function someControllerAction(BrowserslistCheck $browserslistCheck)
{
    $isModern = $browserslistCheck->isModern();
    $isModern = $browserslistCheck->isModern('Explorer', 9); // pls no
}

The user agent parsing will not happen until you call the isModern method without any arguments.

Advanced Symfony, Webpack Encore, and Asset Management Usage

file: config/packages/assets.yaml

framework:
  assets:
    packages:
      modern:
        json_manifest_path: '%kernel.project_dir%/public/build/modern/manifest.json'
      legacy:
        json_manifest_path: '%kernel.project_dir%/public/build/legacy/manifest.json'

file: config/packages/webpack_encore.yaml

webpack_encore:
  output_path: false

  builds:
    modern: '%kernel.project_dir%/public/build/modern/'
    legacy: '%kernel.project_dir%/public/build/legacy/'

  # enable this in config/packages/prod
  #cache: false

file: config/packages/prod/webpack_encore.yaml

webpack_encore:
  cache: true

file: webpack.config.js

const Encore = require('@symfony/webpack-encore')
const buildType = process.env.BROWSERSLIST_ENV
const isModern = buildType === 'modern'

Encore
  // [...]

  .setOutputPath(`public/build/${buildType}/`)
  .setPublicPath(`/build/${buildType}`)
  .setManifestKeyPrefix(`build/${buildType}`)

  // [...]

  // Not required, but ie10 & ie11 have some trouble with data-uris
  .configureImageRule({
    type: isModern ? 'asset' : 'asset/resource',
    maxSize: isModern ? 8 * 1024 : undefined,
    filename: 'images/[name].[contenthash][ext]'
  })

// [...]

file: package.json

{
  /* [...] */
  "scripts": {
    "dev": "BROWSERSLIST_ENV=modern encore dev",
    "watch": "BROWSERSLIST_ENV=modern encore dev --watch",
    "build_modern": "BROWSERSLIST_ENV=modern encore production",
    "build_legacy": "BROWSERSLIST_ENV=legacy encore production",
    "build": "yarn build_modern && yarn build_legacy"
  }
  /* [...] */
}

file: Any base twig template

{% set buildType = is_modern_browser() ? 'modern' : 'legacy' %}

{% block stylesheets %}
    {{ encore_entry_link_tags('css/header', null, buildType) }}
{% endblock %}

{% block javascripts %}
    {{ encore_entry_link_tags('css/main', null, buildType) }}
    
    {% for file in encore_entry_js_files('js/main', buildType) %}
        <script defer
                src="{{ file }}"
                type="application/javascript"
        ></script>
    {% endfor %}
{% endblock %}