diff -u b/core/package.json b/core/package.json
--- b/core/package.json
+++ b/core/package.json
@@ -28,8 +28,12 @@
           "modules": false,
           "targets": {
             "browsers": [
-              "last 2 versions",
-              "ie >= 9"
+              "ie >= 9",
+              "edge >= 13",
+              "firefox >= 5",
+              "opera >= 12",
+              "safari >= 5",
+              "chrome >= 56"
             ]
           }
         }
diff -u b/core/scripts/js/changeOrAdded.js b/core/scripts/js/changeOrAdded.js
--- b/core/scripts/js/changeOrAdded.js
+++ b/core/scripts/js/changeOrAdded.js
@@ -15,6 +15,9 @@
       comments: false
     },
     (err, result) => {
+      if (err) {
+        throw new Error(err);
+      }
       const fileName = filePath.slice(0, -7);
       // Write the result to the filesystem.
       fs.writeFile(`${fileName}.js`, result.code, () => {