Prevent JS minifier making unsafe polyfill changes

We’re seeing the `addEventListener` polyfill not applied in IE8 when UglifyJS `inline` optimisations above level 2 (no variables or statements) are added https://github.com/mishoo/UglifyJS#compress-options
alphagov · Jan 9, 2023 · cf79eeb · cf79eeb
1 parent 32946b6
commit cf79eeb
Showing 1 changed file with 6 additions and 0 deletions.
diff --git a/tasks/compile-javascripts.mjs b/tasks/compile-javascripts.mjs
@@ -104,6 +104,12 @@ export function minifyJavaScript (modulePath, result) {
       includeSources: true
     },
 
+    // Prevent unsafe polyfill changes
+    // https://github.com/mishoo/UglifyJS#compress-options
+    compress: {
+      inline: 2
+    },
+
     // Compatibility workarounds
     ie8: true,
     module: false,