diff --git a/lib/buildlist.js b/lib/buildlist.js
index 2aaf39c..7758a5c 100644
--- a/lib/buildlist.js
+++ b/lib/buildlist.js
@@ -1,5 +1,6 @@
 "use strict";
 var fs = require('fs');
+var path = require('path');

 function Buildlist(options) {
     function requiredOption(name) {
@@ -40,4 +41,19 @@ Buildlist.prototype.reload = function() {
     return delta;
 };

+Buildlist.prototype.filterNonExisting = function() {
+    var deleting = [];
+    this.list.forEach(function (ident, i) {
+        var mypath = path.join(this.baseUrl, ident + '.js');
+        if (!fs.existsSync(mypath)) {
+            deleting.push(i);
+        }
+    });
+    deleting.reverse();
+    deleting.forEach(function (i) {
+        this.list.splice(i, 1);
+    });
+    return this.list;
+};
+
 module.exports = Buildlist;
diff --git a/watcher.js b/watcher.js
index bac35dd..c0bacf3 100644
--- a/watcher.js
+++ b/watcher.js
@@ -212,6 +212,9 @@ var buildlist = new Buildlist({
     baseUrl: baseUrl
 });

+console.log(buildlist.filterNonExisting().length);
+process.exit(0);
+
 var buildQueue = new BuildQueue({
     log: log,
     fs: fileSystem,