diff --git a/lib/extend/injector.js b/lib/extend/injector.js
index 116e39cbff..ed25e1041c 100644
--- a/lib/extend/injector.js
+++ b/lib/extend/injector.js
@@ -1,5 +1,7 @@
 'use strict';
 
+const { Cache } = require('hexo-util');
+
 class Injector {
   constructor() {
     this.store = {
@@ -8,6 +10,8 @@ class Injector {
       body_begin: {},
       body_end: {}
     };
+
+    this.cache = new Cache();
   }
 
   list() {
@@ -33,6 +37,45 @@ class Injector {
     valueSet.add(value);
     entryMap[to] = valueSet;
   }
+
+  exec(data, locals = { page: {} }) {
+    let currentType = 'default';
+    const { page } = locals;
+
+    if (page.__index) currentType = 'home';
+    if (page.__post) currentType = 'post';
+    if (page.__page) currentType = 'page';
+    if (page.archive) currentType = 'archive';
+    if (page.category) currentType = 'category';
+    if (page.tag) currentType = 'tag';
+    if (page.layout) currentType = page.layout;
+
+    const injector = (data, pattern, flag, isBegin = true) => {
+      if (data.includes(`hexo injector ${flag}`)) return data;
+
+      const code = this.cache.apply(`${flag}-${currentType}-code`, () => {
+        const content = currentType === 'default' ? this.getText(flag, 'default') : this.getText(flag, currentType) + this.getText(flag, 'default');
+
+        if (!content.length) return '';
+        return '<!-- hexo injector ' + flag + ' start -->' + content + '<!-- hexo injector ' + flag + ' end -->';
+      });
+
+      // avoid unnesscary replace() for better performance
+      if (!code.length) return data;
+      return data.replace(pattern, str => { return isBegin ? str + code : code + str; });
+    };
+
+    // Inject head_begin
+    data = injector(data, /<head.*?>/, 'head_begin', true);
+    // Inject head_end
+    data = injector(data, '</head>', 'head_end', false);
+    // Inject body_begin
+    data = injector(data, /<body.*?>/, 'body_begin', true);
+    // Inject body_end
+    data = injector(data, '</body>', 'body_end', false);
+
+    return data;
+  }
 }
 
 module.exports = Injector;
diff --git a/lib/hexo/index.js b/lib/hexo/index.js
index 7e442f4ad9..05a2098619 100644
--- a/lib/hexo/index.js
+++ b/lib/hexo/index.js
@@ -25,7 +25,6 @@ const defaultConfig = require('./default_config');
 const loadDatabase = require('./load_database');
 const multiConfigPath = require('./multi_config_path');
 const { sync } = require('resolve');
-const injectorFilter = require('../plugins/injector');
 const { inherits } = require('util');
 const { deepMerge, full_url_for } = require('hexo-util');
 
@@ -57,7 +56,7 @@ const createLoadThemeRoute = function(generatorResult, locals, ctx) {
       if (view) {
         log.debug(`Rendering HTML ${name}: ${magenta(path)}`);
         return view.render(locals)
-          .then(result => injectorFilter.call(ctx, result, locals))
+          .then(result => ctx.extend.injector.exec(result, locals))
           .then(result => ctx.execFilter('after_route_render', result, {
             context: ctx,
             args: [locals]
@@ -225,6 +224,7 @@ class Hexo {
     require('../plugins/filter')(this);
     require('../plugins/generator')(this);
     require('../plugins/helper')(this);
+    require('../plugins/injector')(this);
     require('../plugins/processor')(this);
     require('../plugins/renderer')(this);
     require('../plugins/tag')(this);
diff --git a/lib/plugins/injector/index.js b/lib/plugins/injector/index.js
index 7dc8583a92..be1a9aaca9 100644
--- a/lib/plugins/injector/index.js
+++ b/lib/plugins/injector/index.js
@@ -1,52 +1,6 @@
 'use strict';
 
-const { Cache } = require('hexo-util');
-const cache = new Cache();
-
-function injectFilter(data, locals = { page: {} }) {
-  const Injector = this.extend.injector;
-
-  const current = () => {
-    const { page } = locals;
-
-    if (page.__index) return 'home';
-    if (page.__post) return 'post';
-    if (page.__page) return 'page';
-    if (page.archive) return 'archive';
-    if (page.category) return 'category';
-    if (page.tag) return 'tag';
-    if (page.layout) return page.layout;
-    return 'default';
-  };
-
-  function injector(data, pattern, flag, isBegin = true) {
-    if (data.includes(`hexo injector ${flag}`)) return data;
-
-    const currentType = current();
-    const code = cache.apply(`${flag}-${currentType}-code`, () => {
-      const content = currentType === 'default' ? Injector.getText(flag, 'default') : Injector.getText(flag, currentType) + Injector.getText(flag, 'default');
-
-      if (!content.length) return '';
-
-      return '<!-- hexo injector ' + flag + ' start -->' + content + '<!-- hexo injector ' + flag + ' end -->';
-    });
-
-    // avoid unnesscary replace() for better performance
-    if (!code.length) return data;
-
-    return data.replace(pattern, str => { return isBegin ? str + code : code + str; });
-  }
-
-  // Inject head_begin
-  data = injector(data, /<head.*?>/, 'head_begin', true);
-  // Inject head_end
-  data = injector(data, '</head>', 'head_end', false);
-  // Inject body_begin
-  data = injector(data, /<body.*?>/, 'body_begin', true);
-  // Inject body_end
-  data = injector(data, '</body>', 'body_end', false);
-
-  return data;
-}
-
-module.exports = injectFilter;
+module.exports = ctx => {
+  // eslint-disable-next-line no-unused-vars
+  const { injector } = ctx.extend;
+};
diff --git a/package.json b/package.json
index 6efe4fd042..6ea886e2a8 100644
--- a/package.json
+++ b/package.json
@@ -71,7 +71,6 @@
     "chai": "^4.1.2",
     "chai-as-promised": "^7.1.1",
     "cheerio": "0.22.0",
-    "decache": "^4.5.1",
     "eslint": "^6.0.1",
     "eslint-config-hexo": "^4.1.0",
     "hexo-renderer-marked": "^2.0.0",
diff --git a/test/index.js b/test/index.js
index 6210636470..68b8655b91 100644
--- a/test/index.js
+++ b/test/index.js
@@ -10,7 +10,6 @@ describe('Hexo', () => {
   require('./scripts/generators');
   require('./scripts/helpers');
   require('./scripts/hexo');
-  require('./scripts/injector');
   require('./scripts/models');
   require('./scripts/processors');
   require('./scripts/renderers');
diff --git a/test/scripts/extend/injector.js b/test/scripts/extend/injector.js
index 3b471b986f..900c331f8f 100644
--- a/test/scripts/extend/injector.js
+++ b/test/scripts/extend/injector.js
@@ -1,6 +1,18 @@
 'use strict';
 
 describe('Injector', () => {
+  const content = [
+    '<!DOCTYPE html>',
+    '<html lang="en">',
+    '<head id="head"><title>Test</title>',
+    '</head>',
+    '<body id="body">',
+    '<div></div>',
+    '<p></p>',
+    '</body>',
+    '</html>'
+  ].join('');
+
   const Injector = require('../../../lib/extend/injector');
 
   it('register() - entry is required', () => {
@@ -81,4 +93,145 @@ describe('Injector', () => {
     i.getText('body_end', 'home').should.eql(str);
     i.getText('body_end').should.eql('');
   });
+
+  it('exec() - default', () => {
+    const i = new Injector();
+    const result = i.exec(content);
+    result.should.contain('<head id="head"><title>Test</title></head>');
+    result.should.contain('<body id="body"><div></div><p></p></body>');
+  });
+
+  it('exec() - default', () => {
+    const i = new Injector();
+    const result = i.exec(content);
+    result.should.contain('<head id="head"><title>Test</title></head>');
+    result.should.contain('<body id="body"><div></div><p></p></body>');
+  });
+
+  it('exec() - insert code', () => {
+    const i = new Injector();
+
+    i.register('head_begin', '<!-- Powered by Hexo -->');
+    i.register('head_end', '<link href="prism.css" rel="stylesheet">');
+    i.register('head_end', '<link href="prism-linenumber.css" rel="stylesheet">');
+    i.register('body_begin', '<script>window.Prism = window.Prism || {}; window.Prism.manual = true;</script>');
+    i.register('body_end', '<script src="prism.js"></script>');
+
+    const result = i.exec(content);
+
+    result.should.contain('<head id="head"><!-- hexo injector head_begin start --><!-- Powered by Hexo --><!-- hexo injector head_begin end -->');
+    result.should.contain('<!-- hexo injector head_end start --><link href="prism.css" rel="stylesheet"><link href="prism-linenumber.css" rel="stylesheet"><!-- hexo injector head_end end --></head>');
+    result.should.contain('<body id="body"><!-- hexo injector body_begin start --><script>window.Prism = window.Prism || {}; window.Prism.manual = true;</script><!-- hexo injector body_begin end -->');
+    result.should.contain('<!-- hexo injector body_end start --><script src="prism.js"></script><!-- hexo injector body_end end --></body>');
+  });
+
+  it('exec() - no duplicate insert', () => {
+    const content = [
+      '<!DOCTYPE html>',
+      '<html lang="en">',
+      '<head id="head"><!-- hexo injector head_begin start --><!-- hexo injector head_begin end -->',
+      '<title>Test</title>',
+      '<!-- hexo injector head_end start --><link href="prism.css" rel="stylesheet"></head>',
+      '<body id="body"><!-- hexo injector body_begin start --><!-- hexo injector body_begin end -->',
+      '<div></div>',
+      '<p></p>',
+      '<!-- hexo injector body_end start --><script src="prism.js"></script><!-- hexo injector body_end end --></body>',
+      '</html>'
+    ].join('');
+
+    const i = new Injector();
+
+    i.register('head_begin', '<!-- Powered by Hexo -->');
+    i.register('head_end', '<link href="prism.css" rel="stylesheet">');
+    i.register('head_end', '<link href="prism-linenumber.css" rel="stylesheet">');
+    i.register('body_begin', '<script>window.Prism = window.Prism || {}; window.Prism.manual = true;</script>');
+    i.register('body_end', '<script src="prism.js"></script>');
+
+    const result = i.exec(content);
+
+    result.should.contain('<head id="head"><!-- hexo injector head_begin start --><!-- hexo injector head_begin end -->');
+    result.should.contain('<!-- hexo injector head_end start --><link href="prism.css" rel="stylesheet"></head>');
+    result.should.contain('<body id="body"><!-- hexo injector body_begin start --><!-- hexo injector body_begin end -->');
+    result.should.contain('<!-- hexo injector body_end start --><script src="prism.js"></script><!-- hexo injector body_end end --></body>');
+  });
+
+  it('exec() - multi-line head & body', () => {
+    const content = [
+      '<!DOCTYPE html>',
+      '<html lang="en">',
+      '<head id="head"><title>Test</title>',
+      '</head>',
+      '<body id="body">',
+      '<div></div>',
+      '<p></p>',
+      '</body>',
+      '</html>'
+    ].join('\n');
+
+    const i = new Injector();
+
+    i.register('head_begin', '<!-- Powered by Hexo -->');
+    i.register('head_end', '<link href="prism.css" rel="stylesheet">');
+    i.register('head_end', '<link href="prism-linenumber.css" rel="stylesheet">');
+    i.register('body_begin', '<script>window.Prism = window.Prism || {}; window.Prism.manual = true;</script>');
+    i.register('body_end', '<script src="prism.js"></script>');
+
+    const result = i.exec(content);
+
+    result.should.contain('<head id="head"><!-- hexo injector head_begin start --><!-- Powered by Hexo --><!-- hexo injector head_begin end -->');
+    result.should.contain('<!-- hexo injector head_end start --><link href="prism.css" rel="stylesheet"><link href="prism-linenumber.css" rel="stylesheet"><!-- hexo injector head_end end --></head>');
+    result.should.contain('<body id="body"><!-- hexo injector body_begin start --><script>window.Prism = window.Prism || {}; window.Prism.manual = true;</script><!-- hexo injector body_begin end -->');
+    result.should.contain('<!-- hexo injector body_end start --><script src="prism.js"></script><!-- hexo injector body_end end --></body>');
+  });
+
+  it('exec() - inject on specific page', () => {
+    const content = [
+      '<!DOCTYPE html>',
+      '<html lang="en">',
+      '<head id="head"><title>Test</title>',
+      '</head>',
+      '<body id="body">',
+      '<div></div>',
+      '<p></p>',
+      '</body>',
+      '</html>'
+    ].join('\n');
+
+    const i = new Injector();
+
+    i.register('head_begin', '<!-- head_begin_default -->');
+    i.register('head_begin', '<!-- head_begin_home -->', 'home');
+    i.register('head_begin', '<!-- head_begin_post -->', 'post');
+    i.register('head_begin', '<!-- head_begin_page -->', 'page');
+    i.register('head_begin', '<!-- head_begin_archive -->', 'archive');
+    i.register('head_begin', '<!-- head_begin_category -->', 'category');
+    i.register('head_begin', '<!-- head_begin_tag -->', 'tag');
+
+    const result1 = i.exec(content, { page: {} });
+    const result2 = i.exec(content, { page: { __index: true } });
+    const result3 = i.exec(content, { page: { __post: true } });
+    const result4 = i.exec(content, { page: { __page: true } });
+    const result5 = i.exec(content, { page: { archive: true } });
+    const result6 = i.exec(content, { page: { category: true } });
+    const result7 = i.exec(content, { page: { tag: true } });
+
+    // home
+    result1.should.not.contain('<!-- head_begin_home -->');
+    result2.should.contain('<!-- head_begin_home --><!-- head_begin_default -->');
+    // post
+    result1.should.not.contain('<!-- head_begin_post -->');
+    result3.should.contain('<!-- head_begin_post --><!-- head_begin_default -->');
+    // page
+    result1.should.not.contain('<!-- head_begin_page -->');
+    result4.should.contain('<!-- head_begin_page --><!-- head_begin_default -->');
+    // archive
+    result1.should.not.contain('<!-- head_begin_archive -->');
+    result5.should.contain('<!-- head_begin_archive --><!-- head_begin_default -->');
+    // category
+    result1.should.not.contain('<!-- head_begin_category -->');
+    result6.should.contain('<!-- head_begin_category --><!-- head_begin_default -->');
+    // tag
+    result1.should.not.contain('<!-- head_begin_tag -->');
+    result7.should.contain('<!-- head_begin_tag --><!-- head_begin_default -->');
+  });
 });
diff --git a/test/scripts/injector/index.js b/test/scripts/injector/index.js
deleted file mode 100644
index d5e62a4286..0000000000
--- a/test/scripts/injector/index.js
+++ /dev/null
@@ -1,151 +0,0 @@
-'use strict';
-
-const decache = require('decache');
-
-describe('Injector', () => {
-  const Hexo = require('../../../lib/hexo');
-  let hexo, injectorFilter;
-
-  beforeEach(async () => {
-    await decache('../../../lib/plugins/injector');
-    hexo = new Hexo();
-    injectorFilter = require('../../../lib/plugins/injector').bind(hexo);
-  });
-
-  const content = [
-    '<!DOCTYPE html>',
-    '<html lang="en">',
-    '<head id="head"><title>Test</title>',
-    '</head>',
-    '<body id="body">',
-    '<div></div>',
-    '<p></p>',
-    '</body>',
-    '</html>'
-  ].join('');
-
-  it('default', () => {
-    const result = injectorFilter(content);
-    result.should.contain('<head id="head"><title>Test</title></head>');
-    result.should.contain('<body id="body"><div></div><p></p></body>');
-  });
-
-  it('insert code', () => {
-    hexo.extend.injector.register('head_begin', '<!-- Powered by Hexo -->');
-    hexo.extend.injector.register('head_end', '<link href="prism.css" rel="stylesheet">');
-    hexo.extend.injector.register('head_end', '<link href="prism-linenumber.css" rel="stylesheet">');
-    hexo.extend.injector.register('body_begin', '<script>window.Prism = window.Prism || {}; window.Prism.manual = true;</script>');
-    hexo.extend.injector.register('body_end', '<script src="prism.js"></script>');
-
-    const result = injectorFilter(content);
-
-    result.should.contain('<head id="head"><!-- hexo injector head_begin start --><!-- Powered by Hexo --><!-- hexo injector head_begin end -->');
-    result.should.contain('<!-- hexo injector head_end start --><link href="prism.css" rel="stylesheet"><link href="prism-linenumber.css" rel="stylesheet"><!-- hexo injector head_end end --></head>');
-    result.should.contain('<body id="body"><!-- hexo injector body_begin start --><script>window.Prism = window.Prism || {}; window.Prism.manual = true;</script><!-- hexo injector body_begin end -->');
-    result.should.contain('<!-- hexo injector body_end start --><script src="prism.js"></script><!-- hexo injector body_end end --></body>');
-  });
-
-  it('no duplicate insert', () => {
-    const content = [
-      '<!DOCTYPE html>',
-      '<html lang="en">',
-      '<head id="head"><!-- hexo injector head_begin start --><!-- hexo injector head_begin end -->',
-      '<title>Test</title>',
-      '<!-- hexo injector head_end start --><link href="prism.css" rel="stylesheet"></head>',
-      '<body id="body"><!-- hexo injector body_begin start --><!-- hexo injector body_begin end -->',
-      '<div></div>',
-      '<p></p>',
-      '<!-- hexo injector body_end start --><script src="prism.js"></script><!-- hexo injector body_end end --></body>',
-      '</html>'
-    ].join('');
-
-    hexo.extend.injector.register('head_begin', '<!-- Powered by Hexo -->');
-    hexo.extend.injector.register('head_end', '<link href="prism.css" rel="stylesheet">');
-    hexo.extend.injector.register('head_end', '<link href="prism-linenumber.css" rel="stylesheet">');
-    hexo.extend.injector.register('body_begin', '<script>window.Prism = window.Prism || {}; window.Prism.manual = true;</script>');
-    hexo.extend.injector.register('body_end', '<script src="prism.js"></script>');
-
-    const result = injectorFilter(content);
-
-    result.should.contain('<head id="head"><!-- hexo injector head_begin start --><!-- hexo injector head_begin end -->');
-    result.should.contain('<!-- hexo injector head_end start --><link href="prism.css" rel="stylesheet"></head>');
-    result.should.contain('<body id="body"><!-- hexo injector body_begin start --><!-- hexo injector body_begin end -->');
-    result.should.contain('<!-- hexo injector body_end start --><script src="prism.js"></script><!-- hexo injector body_end end --></body>');
-  });
-
-  it('multi-line head & body', () => {
-    const content = [
-      '<!DOCTYPE html>',
-      '<html lang="en">',
-      '<head id="head"><title>Test</title>',
-      '</head>',
-      '<body id="body">',
-      '<div></div>',
-      '<p></p>',
-      '</body>',
-      '</html>'
-    ].join('\n');
-
-    hexo.extend.injector.register('head_begin', '<!-- Powered by Hexo -->');
-    hexo.extend.injector.register('head_end', '<link href="prism.css" rel="stylesheet">');
-    hexo.extend.injector.register('head_end', '<link href="prism-linenumber.css" rel="stylesheet">');
-    hexo.extend.injector.register('body_begin', '<script>window.Prism = window.Prism || {}; window.Prism.manual = true;</script>');
-    hexo.extend.injector.register('body_end', '<script src="prism.js"></script>');
-
-    const result = injectorFilter(content);
-
-    result.should.contain('<head id="head"><!-- hexo injector head_begin start --><!-- Powered by Hexo --><!-- hexo injector head_begin end -->');
-    result.should.contain('<!-- hexo injector head_end start --><link href="prism.css" rel="stylesheet"><link href="prism-linenumber.css" rel="stylesheet"><!-- hexo injector head_end end --></head>');
-    result.should.contain('<body id="body"><!-- hexo injector body_begin start --><script>window.Prism = window.Prism || {}; window.Prism.manual = true;</script><!-- hexo injector body_begin end -->');
-    result.should.contain('<!-- hexo injector body_end start --><script src="prism.js"></script><!-- hexo injector body_end end --></body>');
-  });
-
-  it('inject on specific page', () => {
-    const content = [
-      '<!DOCTYPE html>',
-      '<html lang="en">',
-      '<head id="head"><title>Test</title>',
-      '</head>',
-      '<body id="body">',
-      '<div></div>',
-      '<p></p>',
-      '</body>',
-      '</html>'
-    ].join('\n');
-
-    hexo.extend.injector.register('head_begin', '<!-- head_begin_default -->');
-    hexo.extend.injector.register('head_begin', '<!-- head_begin_home -->', 'home');
-    hexo.extend.injector.register('head_begin', '<!-- head_begin_post -->', 'post');
-    hexo.extend.injector.register('head_begin', '<!-- head_begin_page -->', 'page');
-    hexo.extend.injector.register('head_begin', '<!-- head_begin_archive -->', 'archive');
-    hexo.extend.injector.register('head_begin', '<!-- head_begin_category -->', 'category');
-    hexo.extend.injector.register('head_begin', '<!-- head_begin_tag -->', 'tag');
-
-    const result1 = injectorFilter(content, { page: {} });
-    const result2 = injectorFilter(content, { page: { __index: true } });
-    const result3 = injectorFilter(content, { page: { __post: true } });
-    const result4 = injectorFilter(content, { page: { __page: true } });
-    const result5 = injectorFilter(content, { page: { archive: true } });
-    const result6 = injectorFilter(content, { page: { category: true } });
-    const result7 = injectorFilter(content, { page: { tag: true } });
-
-    // home
-    result1.should.not.contain('<!-- head_begin_home -->');
-    result2.should.contain('<!-- head_begin_home --><!-- head_begin_default -->');
-    // post
-    result1.should.not.contain('<!-- head_begin_post -->');
-    result3.should.contain('<!-- head_begin_post --><!-- head_begin_default -->');
-    // page
-    result1.should.not.contain('<!-- head_begin_page -->');
-    result4.should.contain('<!-- head_begin_page --><!-- head_begin_default -->');
-    // archive
-    result1.should.not.contain('<!-- head_begin_archive -->');
-    result5.should.contain('<!-- head_begin_archive --><!-- head_begin_default -->');
-    // category
-    result1.should.not.contain('<!-- head_begin_category -->');
-    result6.should.contain('<!-- head_begin_category --><!-- head_begin_default -->');
-    // tag
-    result1.should.not.contain('<!-- head_begin_tag -->');
-    result7.should.contain('<!-- head_begin_tag --><!-- head_begin_default -->');
-  });
-});