diff --git a/.eslintignore b/.eslintignore
index 642271f..92872bb 100644
--- a/.eslintignore
+++ b/.eslintignore
@@ -1,2 +1,3 @@
 node_modules/
-coverage/
\ No newline at end of file
+coverage/
+.nyc_output
diff --git a/lib/dom-filter.js b/lib/dom-filter.js
index 2d23cb3..85fd9a3 100644
--- a/lib/dom-filter.js
+++ b/lib/dom-filter.js
@@ -6,10 +6,10 @@ const CSSselect = require('css-select');
 class Filter {
   constructor(hexo, excludes) {
     this.hexo = hexo;
-    this.selectors = excludes.map(this._compile);
+    this.selectors = excludes.map(this._compile.bind(this));
   }
 
-  _compile = selector => {
+  _compile(selector) {
     try {
       return CSSselect.compile(selector);
     } catch (err) {
@@ -18,18 +18,18 @@ class Filter {
     }
   }
 
-  match = node => {
+  match(node) {
     // not match any
     return !this.selectors.some(s => s(node));
   }
 
-  filter = nodes => {
+  filter(nodes) {
     // remove inner nodes that doesn't match
     domutils.filter(n => !this.match(n), nodes)
       .forEach(node => domutils.removeElement(node));
 
     // only keep top level nodes that match
-    return nodes.filter(this.match);
+    return nodes.filter(this.match.bind(this));
   }
 }