1 files changed, 2 insertions, 2 deletions
diff --git a/lib/HostMap.jsm b/lib/HostMap.jsm
index 59d4f65..ecbce25 100644
--- a/lib/HostMap.jsm
+++ b/lib/HostMap.jsm
@@ -31,7 +31,7 @@ var map = new Map();
 
 var HostMap = {
     put: function (key, value) {
-        if (!(key instanceof Ci.nsIURI) || !(value instanceof Ci.nsIURI)
+        if (typeof key !== 'string' || !(value instanceof Ci.nsIURI)
             || !key || !value) {
             throw new Error('invalid argument(s)');
         }
@@ -43,7 +43,7 @@ var HostMap = {
         map.set(key, value);
     },
     get: function (key) {
-        if (!(key instanceof Ci.nsIURI) || !key) {
+        if (typeof key !== 'string' || !key) {
             throw new Error('invalid argument');
         }