From e7a99b3c6f4720492c9329b92900ad6d3821cc8d Mon Sep 17 00:00:00 2001
From: Jon Moss <me@jonathanmoss.me>
Date: Mon, 11 Dec 2017 17:20:39 -0500
Subject: [PATCH] tools: add number-isnan rule

PR-URL: https://github.com/nodejs/node/pull/17556
Reviewed-By: Rich Trott <rtrott@gmail.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
---
 test/.eslintrc.yaml                       |  1 +
 test/parallel/test-eslint-number-isnan.js | 20 ++++++++++++++++++++
 tools/eslint-rules/number-isnan.js        | 14 ++++++++++++++
 3 files changed, 35 insertions(+)
 create mode 100644 test/parallel/test-eslint-number-isnan.js
 create mode 100644 tools/eslint-rules/number-isnan.js

diff --git a/test/.eslintrc.yaml b/test/.eslintrc.yaml
index 7a5d002e1b51e8..dbcb8ea6e0aa87 100644
--- a/test/.eslintrc.yaml
+++ b/test/.eslintrc.yaml
@@ -14,6 +14,7 @@ rules:
   prefer-common-mustnotcall: error
   crypto-check: error
   inspector-check: error
+  number-isnan: error
   ## common module is mandatory in tests
   required-modules: [error, common]
 
diff --git a/test/parallel/test-eslint-number-isnan.js b/test/parallel/test-eslint-number-isnan.js
new file mode 100644
index 00000000000000..deeac48bcccb68
--- /dev/null
+++ b/test/parallel/test-eslint-number-isnan.js
@@ -0,0 +1,20 @@
+'use strict';
+
+require('../common');
+
+const RuleTester = require('../../tools/eslint').RuleTester;
+const rule = require('../../tools/eslint-rules/number-isnan');
+
+const message = 'Please use Number.isNaN instead of the global isNaN function';
+
+new RuleTester().run('number-isnan', rule, {
+  valid: [
+    'Number.isNaN()'
+  ],
+  invalid: [
+    {
+      code: 'isNaN()',
+      errors: [{ message }]
+    }
+  ]
+});
diff --git a/tools/eslint-rules/number-isnan.js b/tools/eslint-rules/number-isnan.js
new file mode 100644
index 00000000000000..885c38be8b2384
--- /dev/null
+++ b/tools/eslint-rules/number-isnan.js
@@ -0,0 +1,14 @@
+'use strict';
+
+const astSelector = "CallExpression[callee.name='isNaN']";
+const msg = 'Please use Number.isNaN instead of the global isNaN function';
+
+module.exports = function(context) {
+  function report(node) {
+    context.report(node, msg);
+  }
+
+  return {
+    [astSelector]: report
+  };
+};