diff -u b/core/assets/vendor/jquery.ui/ui/data.js b/core/assets/vendor/jquery.ui/ui/data.js
--- b/core/assets/vendor/jquery.ui/ui/data.js
+++ b/core/assets/vendor/jquery.ui/ui/data.js
@@ -15,25 +15,25 @@
 ( function( factory ) {
-  if ( typeof define === "function" && define.amd ) {
+	if ( typeof define === "function" && define.amd ) {
 
-    // AMD. Register as an anonymous module.
-    define( [ "jquery", "./version" ], factory );
-  } else {
+		// AMD. Register as an anonymous module.
+		define( [ "jquery", "./version" ], factory );
+	} else {
 
-    // Browser globals
-    factory( jQuery );
-  }
+		// Browser globals
+		factory( jQuery );
+	}
 } ( function( $ ) {
-  return $.extend( $.expr[ ":" ], {
-    data: $.expr.createPseudo ?
-      $.expr.createPseudo( function( dataName ) {
-        return function( elem ) {
-          return !!$.data( elem, dataName );
-        };
-      } ) :
+return $.extend( $.expr[ ":" ], {
+	data: $.expr.createPseudo ?
+		$.expr.createPseudo( function( dataName ) {
+			return function( elem ) {
+				return !!$.data( elem, dataName );
+			};
+		} ) :
 
-      // Support: jQuery <1.8
-      function( elem, i, match ) {
-        return !!$.data( elem, match[ 3 ] );
-      }
-  } );
+		// Support: jQuery <1.8
+		function( elem, i, match ) {
+			return !!$.data( elem, match[ 3 ] );
+		}
+} );
 } ) );
diff -u b/core/scripts/js/jqueryui-build.js b/core/scripts/js/jqueryui-build.js
--- b/core/scripts/js/jqueryui-build.js
+++ b/core/scripts/js/jqueryui-build.js
@@ -6,8 +6,10 @@
  * Run build:jqueryui with --file to only parse a specific file.
  * @example <caption>Only process assets/vendor/jquery.ui/ui/widget.js and
  * assets/vendor/jquery.ui/ui/plugin.js</caption
- * yarn run build:jqueryui -- --file assets/vendor/jquery.ui/ui/widget.js --file
+ * yarn run build:jqueryui --file assets/vendor/jquery.ui/ui/widget.js --file
  * assets/vendor/jquery.ui/ui/plugin.js
+ * @example <caption>Check if all files have been compiled correctly</caption
+ * yarn run build:jqueryui --check
  *
  * @internal This file is part of the core javascript build process and is only
  * meant to be used in that context.
@@ -17,6 +19,7 @@
 
 const glob = require('glob');
 const argv = require('minimist')(process.argv.slice(2));
+const check = require('./jqueryui-check');
 const minify = require('./jqueryui-terser');
 const log = require('./log');
 
@@ -28,12 +31,16 @@
   }
   // Process all the found files.
-  filePaths.forEach(minify);
+  let callback = minify;
+  if (argv.check) {
+    callback = check;
+  }
+  filePaths.forEach(callback);
 };
 
 if (argv.file) {
   processFiles(null, [].concat(argv.file));
 }
 else {
-  glob(fileMatch, { ignore: ['./**/i18n/*']}, processFiles);
+  glob(fileMatch, {}, processFiles);
 }
 process.exitCode = 0;
only in patch2:
unchanged:
--- /dev/null
+++ b/core/scripts/js/jqueryui-check.js
@@ -0,0 +1,23 @@
+const chalk = require('chalk');
+const fs = require('fs');
+const log = require('./log');
+const Terser = require('terser');
+
+module.exports = filePath => {
+  log(`'${filePath}' is being checked.`);
+  // Transform the file.
+  const file = fs.readFileSync(filePath, 'utf-8');
+  const result = Terser.minify(file);
+  const fileName = filePath.slice(0, -3);
+  fs.readFile(`${fileName}-min.js`, function read(err, data) {
+    if (err) {
+      log(chalk.red(err));
+      process.exitCode = 1;
+      return;
+    }
+    if (result.code !== data.toString()) {
+      log(chalk.red(`'${filePath}' is not updated.`));
+      process.exitCode = 1;
+    }
+  });
+};