Move Autoprefixer settings out of Gruntfile.js and into a separate file

Refs #18584
Closes #18659

[skip sauce]
[skip validator]

2 files changed, 35 insertions, 31 deletions

diff --git a/Gruntfile.js b/Gruntfile.js
index aae5b5479..53e420974 100644
--- a/Gruntfile.js
+++ b/Gruntfile.js
@@ -21,37 +21,8 @@ module.exports = function (grunt) {
   var isTravis = require('is-travis');
   var npmShrinkwrap = require('npm-shrinkwrap');
   var mq4HoverShim = require('mq4-hover-shim');
-  var autoprefixer = require('autoprefixer')({
-    browsers: [
-      //
-      // Official browser support policy:
-      // http://v4-alpha.getbootstrap.com/getting-started/browsers-devices/#supported-browsers
-      //
-      'Chrome >= 35', // Exact version number here is kinda arbitrary
-      // Rather than using Autoprefixer's native "Firefox ESR" version specifier string,
-      // we deliberately hardcode the number. This is to avoid unwittingly severely breaking the previous ESR in the event that:
-      // (a) we happen to ship a new Bootstrap release soon after the release of a new ESR,
-      //     such that folks haven't yet had a reasonable amount of time to upgrade; and
-      // (b) the new ESR has unprefixed CSS properties/values whose absence would severely break webpages
-      //     (e.g. `box-sizing`, as opposed to `background: linear-gradient(...)`).
-      //     Since they've been unprefixed, Autoprefixer will stop prefixing them,
-      //     thus causing them to not work in the previous ESR (where the prefixes were required).
-      'Firefox >= 31', // Current Firefox Extended Support Release (ESR)
-      // Note: Edge versions in Autoprefixer & Can I Use refer to the EdgeHTML rendering engine version,
-      // NOT the Edge app version shown in Edge's "About" screen.
-      // For example, at the time of writing, Edge 20 on an up-to-date system uses EdgeHTML 12.
-      // See also https://github.com/Fyrd/caniuse/issues/1928
-      'Edge >= 12',
-      'Explorer >= 9',
-      // Out of leniency, we prefix these 1 version further back than the official policy.
-      'iOS >= 8',
-      'Safari >= 8',
-      // The following remain NOT officially supported, but we're lenient and include their prefixes to avoid severely breaking in them.
-      'Android 2.3',
-      'Android >= 4',
-      'Opera >= 12'
-    ]
-  });
+  var autoprefixerSettings = require('./grunt/autoprefixer-settings.js');
+  var autoprefixer = require('autoprefixer')(autoprefixerSettings.settings);
 
   var generateCommonJSModule = require('./grunt/bs-commonjs-generator.js');
   var configBridge = grunt.file.readJSON('./grunt/configBridge.json', { encoding: 'utf8' });
diff --git a/grunt/autoprefixer-settings.js b/grunt/autoprefixer-settings.js
new file mode 100644
index 000000000..2988d3b2b
--- /dev/null
+++ b/grunt/autoprefixer-settings.js
@@ -0,0 +1,33 @@
+module.exports = {
+  settings: {
+    browsers: [
+      //
+      // Official browser support policy:
+      // http://v4-alpha.getbootstrap.com/getting-started/browsers-devices/#supported-browsers
+      //
+      'Chrome >= 35', // Exact version number here is kinda arbitrary
+      // Rather than using Autoprefixer's native "Firefox ESR" version specifier string,
+      // we deliberately hardcode the number. This is to avoid unwittingly severely breaking the previous ESR in the event that:
+      // (a) we happen to ship a new Bootstrap release soon after the release of a new ESR,
+      //     such that folks haven't yet had a reasonable amount of time to upgrade; and
+      // (b) the new ESR has unprefixed CSS properties/values whose absence would severely break webpages
+      //     (e.g. `box-sizing`, as opposed to `background: linear-gradient(...)`).
+      //     Since they've been unprefixed, Autoprefixer will stop prefixing them,
+      //     thus causing them to not work in the previous ESR (where the prefixes were required).
+      'Firefox >= 31', // Current Firefox Extended Support Release (ESR)
+      // Note: Edge versions in Autoprefixer & Can I Use refer to the EdgeHTML rendering engine version,
+      // NOT the Edge app version shown in Edge's "About" screen.
+      // For example, at the time of writing, Edge 20 on an up-to-date system uses EdgeHTML 12.
+      // See also https://github.com/Fyrd/caniuse/issues/1928
+      'Edge >= 12',
+      'Explorer >= 9',
+      // Out of leniency, we prefix these 1 version further back than the official policy.
+      'iOS >= 8',
+      'Safari >= 8',
+      // The following remain NOT officially supported, but we're lenient and include their prefixes to avoid severely breaking in them.
+      'Android 2.3',
+      'Android >= 4',
+      'Opera >= 12'
+      ]
+  }
+}