Merge pull request #13 from Yvem/patch-1

bug(prune): handle OSes on whom fs.stats hasn't birthTime

Author: Offirmo

lib/prune-cache.js

@@ -21,7 +21,8 @@ function pruneCache(npmPkgrCache, cb) {
       monthAgo.setMonth(monthAgo.getMonth() - 1);
 
       var oldCache = results.reduce(function (res, curr, idx) {
-        return (curr.birthtime.getTime() - monthAgo < 0) ?
+        var creationTime = curr.birthtime || curr.mtime;
+        return (creationTime.getTime() - monthAgo < 0) ?
           res.concat([ cacheFolders[idx] ]) : res;
       }, []);