diff --git a/lib/utils/common.js b/lib/utils/common.js
index 408f154..59dd7f7 100644
--- a/lib/utils/common.js
+++ b/lib/utils/common.js
@@ -26,7 +26,24 @@ utils.common = {
     return list
   },
   quote: function (obj) {
-    return JSON.stringify(obj)
+    function escapeString (s) {
+      let escaped = s.replace(/\\/g, '\\\\')
+        .replace(/\"/g, '\\\"') // eslint-disable-line no-useless-escape
+        .replace(/\0/g, '\\0')
+        .replace(/\n/g, '\\n')
+        .replace(/[^\0-~]/g, function (ch) {
+          return '\\u' + ('000' + ch.charCodeAt(0).toString(16)).slice(-4)
+        })
+
+      return '\"' + escaped + '\"' // eslint-disable-line no-useless-escape
+    }
+
+    if (typeof s === 'string') {
+      return escapeString(obj)
+    } else {
+      // For other things (such as numbers, |null|, and |undefined|), stringify
+      return JSON.stringify(obj)
+    }
   },
   b64encode: function (str) {
     // Unicode safe b64 encoding