diff --git a/lib/js-yaml/type/js/function.js b/lib/js-yaml/type/js/function.js
index 3604e233..8fab8c43 100644
--- a/lib/js-yaml/type/js/function.js
+++ b/lib/js-yaml/type/js/function.js
@@ -14,7 +14,8 @@ try {
   var _require = require;
   esprima = _require('esprima');
 } catch (_) {
-  /*global window */
+  /* eslint-disable no-redeclare */
+  /* global window */
   if (typeof window !== 'undefined') esprima = window.esprima;
 }
 
diff --git a/package.json b/package.json
index dd5bd4a5..ba2621fd 100644
--- a/package.json
+++ b/package.json
@@ -37,10 +37,10 @@
     "benchmark": "^2.1.4",
     "browserify": "^16.2.2",
     "codemirror": "^5.13.4",
-    "eslint": "^4.1.1",
-    "fast-check": "1.1.3",
+    "eslint": "^7.0.0",
+    "fast-check": "^1.24.2",
     "istanbul": "^0.4.5",
-    "mocha": "^5.2.0",
+    "mocha": "^7.1.2",
     "uglify-js": "^3.0.1"
   },
   "scripts": {
diff --git a/support/demo_template/base64.js b/support/demo_template/base64.js
index 572acc66..c0528ceb 100644
--- a/support/demo_template/base64.js
+++ b/support/demo_template/base64.js
@@ -30,8 +30,8 @@
 
 'use strict';
 
-/*global window*/
-/*eslint-disable no-bitwise*/
+/* eslint-env browser */
+/* eslint-disable no-bitwise */
 
 function noop() {}
 
diff --git a/support/demo_template/demo.js b/support/demo_template/demo.js
index d388d5cb..6b5df324 100644
--- a/support/demo_template/demo.js
+++ b/support/demo_template/demo.js
@@ -1,6 +1,6 @@
-/*global window, document, location*/
 'use strict';
 
+/* eslint-env browser */
 
 var jsyaml     = require('../../');
 var codemirror = require('codemirror');