From 718a216797bea169b3a59f8034a487c8d8529385 Mon Sep 17 00:00:00 2001
From: Melvin Philips <melvin0008@gmail.com>
Date: Thu, 5 Oct 2017 14:17:39 -0700
Subject: [PATCH] Refactor is.domElement to declare constants outside the
 function

---
 index.js | 9 +++++----
 test.js  | 7 +++++--
 2 files changed, 10 insertions(+), 6 deletions(-)

diff --git a/index.js b/index.js
index 47b95f7..fab9230 100644
--- a/index.js
+++ b/index.js
@@ -161,11 +161,12 @@ is.inRange = (x, range) => {
 	throw new TypeError(`Invalid range: ${util.inspect(range)}`);
 };
 
+const NODE_TYPE_ELEMENT_NODE = 1;
+const DOM_PROPERTIES_TO_CHECK = ['innerHTML', 'ownerDocument', 'style', 'attributes', 'nodeValue'];
+
 is.domElement = x => {
-	const ELEMENT_NODE = 1;
-	const propsToCheck = ['innerHTML', 'ownerDocument', 'style', 'attributes', 'nodeValue'];
-	return is.object(x) && x.nodeType === ELEMENT_NODE && is.string(x.nodeName) &&
-				!is.plainObject(x) && propsToCheck.every(prop => prop in x);
+	return is.object(x) && x.nodeType === NODE_TYPE_ELEMENT_NODE && is.string(x.nodeName) &&
+				!is.plainObject(x) && DOM_PROPERTIES_TO_CHECK.every(property => property in x);
 };
 
 is.infinite = x => x === Infinity || x === -Infinity;
diff --git a/test.js b/test.js
index abadfa3..d026968 100644
--- a/test.js
+++ b/test.js
@@ -9,6 +9,7 @@ const PromiseSubclassFixture = class extends Promise {};
 const ErrorSubclassFixture = class extends Error {};
 
 const document = jsdom();
+const createDomElement = el => document.createElement(el);
 
 const types = new Map([
 	['undefined', undefined],
@@ -93,12 +94,14 @@ const types = new Map([
 		new Object() // eslint-disable-line no-new-object
 	]],
 	['integer', 6],
-	['domElement', ['div',
+	['domElement', [
+		'div',
 		'input',
 		'span',
 		'img',
 		'canvas',
-		'script'].map(el => document.createElement(el))],
+		'script'
+	].map(createDomElement)],
 	['non-domElements', [
 		document.createTextNode('data'),
 		document.createProcessingInstruction('xml-stylesheet', 'href="mycss.css" type="text/css"'),