From 0b7940b6e9f3bc87529c8e8e03ab5e9754add261 Mon Sep 17 00:00:00 2001
From: Mathias Bynens <mathias@qiwi.be>
Date: Tue, 21 Jun 2016 20:39:44 +0200
Subject: [PATCH] Match the updated specification

https://html.spec.whatwg.org/multipage/scripting.html#valid-custom-element-name

See https://github.com/w3c/webcomponents/issues/239 for background.
---
 index.js     | 9 +++++----
 package.json | 4 ++--
 test.js      | 3 ++-
 3 files changed, 9 insertions(+), 7 deletions(-)

diff --git a/index.js b/index.js
index cee766c..2c9ba50 100644
--- a/index.js
+++ b/index.js
@@ -1,6 +1,7 @@
 'use strict';
-var ncname = require('ncname');
+var isPotentialCustomElementName = require('is-potential-custom-element-name');
 
+// https://html.spec.whatwg.org/multipage/scripting.html#valid-custom-element-name
 var reservedNames = [
 	'annotation-xml',
 	'color-profile',
@@ -33,13 +34,13 @@ function hasError(name) {
 		return 'Custom element names must not start with a hyphen.';
 	}
 
-	// http://www.w3.org/TR/custom-elements/#concepts
-	if (!ncname.test(name)) {
+	// https://html.spec.whatwg.org/multipage/scripting.html#prod-potentialcustomelementname
+	if (!isPotentialCustomElementName(name)) {
 		return 'Invalid element name.';
 	}
 
 	if (reservedNames.indexOf(name) !== -1) {
-		return 'The supplied element name is reserved and can\'t be used.\nSee: http://www.w3.org/TR/custom-elements/#concepts';
+		return 'The supplied element name is reserved and can\'t be used.\nSee: https://html.spec.whatwg.org/multipage/scripting.html#valid-custom-element-name';
 	}
 }
 
diff --git a/package.json b/package.json
index d46b4c6..e2bf873 100644
--- a/package.json
+++ b/package.json
@@ -41,9 +41,9 @@
     "components"
   ],
   "dependencies": {
+    "is-potential-custom-element-name": "^1.0.0",
     "log-symbols": "^1.0.0",
-    "meow": "^3.3.0",
-    "ncname": "^1.0.0"
+    "meow": "^3.3.0"
   },
   "devDependencies": {
     "mocha": "*"
diff --git a/test.js b/test.js
index 794b58f..5d1014d 100644
--- a/test.js
+++ b/test.js
@@ -35,7 +35,7 @@ it('should return true for `isValid` with warnings for not recommended names', f
 	assert(validate('uni--corn').message);
 	assert(validate('uni-----corn').message);
 	assert(validate('uni-co___rn').message);
-	assert(validate('øl-unicorn').isValid);
+	assert(!validate('øl-unicorn').isValid);
 	assert(validate('øl-unicorn').message);
 	assert(validate('uni-co.rn').isValid);
 	assert(validate('uni-co.rn').message);
@@ -43,4 +43,5 @@ it('should return true for `isValid` with warnings for not recommended names', f
 	assert(validate('uni-corné').message);
 	assert(validate('xml-unicorn').isValid);
 	assert(validate('xml-unicorn').message);
+	assert(validate('foo-💩').message);
 });