Merge pull request #317 from catchonme/master

修复filter过滤失败问题

src/utils/tpl-builtin.ts

@@ -232,7 +232,7 @@ export const filters: {
                 arg1 = expOrDirective;
             }
             arg1 = arg1 ? (/^('|")(.*)\1$/.test(arg1) ? RegExp.$2 : resolveVariable(arg1, this as any)) : '';
-            fn = value => !!~String(value.toLowerCase()).indexOf(arg1);
+            fn = value => !!~String(value).toLowerCase().indexOf(arg1);
         }
 
         keys = keys.split(/\s*,\s*/);