From 30572a045ddeb5580dec2492b1201253bb895345 Mon Sep 17 00:00:00 2001
From: Bjorn Stromberg <bjorn@bjornstar.com>
Date: Sun, 7 Jun 2020 14:41:07 +0900
Subject: [PATCH] Fix is.domElement to more accurately reflect that the object
 is an HTMLElement

---
 source/index.ts | 24 +++++++++++++++++-------
 test/test.ts    | 23 +++++++++++------------
 2 files changed, 28 insertions(+), 19 deletions(-)

diff --git a/source/index.ts b/source/index.ts
index 0ec3a9e..8d83e93 100644
--- a/source/index.ts
+++ b/source/index.ts
@@ -60,6 +60,7 @@ const objectTypeNames = [
 	'DataView',
 	'Promise',
 	'URL',
+	'HTMLElement',
 	...typedArrayTypeNames
 ] as const;
 
@@ -102,6 +103,10 @@ const isOfType = <T>(type: string) => (value: unknown): value is T => typeof val
 const getObjectType = (value: unknown): ObjectTypeName | undefined => {
 	const objectTypeName = toString.call(value).slice(8, -1);
 
+	if (/HTML\w+Element/.test(objectTypeName) && is.domElement(value)) {
+		return 'HTMLElement';
+	}
+
 	if (isObjectTypeName(objectTypeName)) {
 		return objectTypeName;
 	}
@@ -268,7 +273,7 @@ is.safeInteger = (value: unknown): value is number => Number.isSafeInteger(value
 
 is.plainObject = <Value = unknown>(value: unknown): value is Record<string, Value> => {
 	// From: https://github.com/sindresorhus/is-plain-obj/blob/master/index.js
-	if (getObjectType(value) !== 'Object') {
+	if (toString.call(value) !== '[object Object]') {
 		return false;
 	}
 
@@ -300,7 +305,7 @@ is.inRange = (value: number, range: number | number[]): value is number => {
 };
 
 const NODE_TYPE_ELEMENT = 1;
-const DOM_PROPERTIES_TO_CHECK = [
+const DOM_PROPERTIES_TO_CHECK: Array<(keyof HTMLElement)> = [
 	'innerHTML',
 	'ownerDocument',
 	'style',
@@ -308,8 +313,13 @@ const DOM_PROPERTIES_TO_CHECK = [
 	'nodeValue'
 ];
 
-is.domElement = (value: unknown): value is Element => is.object(value) && (value as Element).nodeType === NODE_TYPE_ELEMENT && is.string((value as Element).nodeName) &&
-	!is.plainObject(value) && DOM_PROPERTIES_TO_CHECK.every(property => property in (value as Element));
+is.domElement = (value: unknown): value is HTMLElement => {
+	return is.object(value) &&
+	(value as HTMLElement).nodeType === NODE_TYPE_ELEMENT &&
+	is.string((value as HTMLElement).nodeName) &&
+	!is.plainObject(value) &&
+	DOM_PROPERTIES_TO_CHECK.every(property => property in value);
+};
 
 export interface ObservableLike {
 	subscribe(observer: (value: unknown) => void): void;
@@ -416,7 +426,7 @@ export const enum AssertionTypeDescription {
 	plainObject = 'plain object',
 	arrayLike = 'array-like',
 	typedArray = 'TypedArray',
-	domElement = 'Element',
+	domElement = 'HTMLElement',
 	nodeStream = 'Node.js Stream',
 	infinite = 'infinite number',
 	emptyArray = 'empty array',
@@ -503,7 +513,7 @@ interface Assert {
 	plainObject: <Value = unknown>(value: unknown) => asserts value is Record<string, Value>;
 	typedArray: (value: unknown) => asserts value is TypedArray;
 	arrayLike: <T = unknown>(value: unknown) => asserts value is ArrayLike<T>;
-	domElement: (value: unknown) => asserts value is Element;
+	domElement: (value: unknown) => asserts value is HTMLElement;
 	observable: (value: unknown) => asserts value is ObservableLike;
 	nodeStream: (value: unknown) => asserts value is NodeStream;
 	infinite: (value: unknown) => asserts value is number;
@@ -593,7 +603,7 @@ export const assert: Assert = {
 	plainObject: <Value = unknown>(value: unknown): asserts value is Record<string, Value> => assertType(is.plainObject(value), AssertionTypeDescription.plainObject, value),
 	typedArray: (value: unknown): asserts value is TypedArray => assertType(is.typedArray(value), AssertionTypeDescription.typedArray, value),
 	arrayLike: <T = unknown>(value: unknown): asserts value is ArrayLike<T> => assertType(is.arrayLike(value), AssertionTypeDescription.arrayLike, value),
-	domElement: (value: unknown): asserts value is Element => assertType(is.domElement(value), AssertionTypeDescription.domElement, value),
+	domElement: (value: unknown): asserts value is HTMLElement => assertType(is.domElement(value), AssertionTypeDescription.domElement, value),
 	observable: (value: unknown): asserts value is ObservableLike => assertType(is.observable(value), 'Observable', value),
 	nodeStream: (value: unknown): asserts value is NodeStream => assertType(is.nodeStream(value), AssertionTypeDescription.nodeStream, value),
 	infinite: (value: unknown): asserts value is number => assertType(is.infinite(value), AssertionTypeDescription.infinite, value),
diff --git a/test/test.ts b/test/test.ts
index 9b0d055..64c84bc 100644
--- a/test/test.ts
+++ b/test/test.ts
@@ -591,7 +591,7 @@ const testType = (t: ExecutionContext, type: string, exclude?: string[]) => {
 			}
 
 			if (isTypeUnderTest && typename) {
-				t.is(is(fixture), typename);
+				t.is<TypeName>(is(fixture), typename);
 			}
 		}
 	}
@@ -1275,18 +1275,17 @@ test('is.domElement', t => {
 		assert.domElement({nodeType: 1, nodeName: 'div'});
 	});
 
-	const htmlTagNameToTypeName = {
-		div: 'HTMLDivElement',
-		input: 'HTMLInputElement',
-		span: 'HTMLSpanElement',
-		img: 'HTMLImageElement',
-		canvas: 'HTMLCanvasElement',
-		script: 'HTMLScriptElement'
-	};
+	const tagNames = [
+		'div',
+		'input',
+		'span',
+		'img',
+		'canvas',
+		'script'
+	];
 
-	for (const [tagName, typeName] of Object.entries(htmlTagNameToTypeName)) {
-		const domElement = createDomElement(tagName);
-		t.is(is(domElement), typeName);
+	for (const tagName of tagNames) {
+		t.is<TypeName>(is(createDomElement(tagName)), 'HTMLElement');
 	}
 });