backport #3956

src/create-element.js

@@ -1,5 +1,6 @@
 import { UNDEFINED } from './constants';
 import options from './options';
+import { isArray } from './util';
 
 let vnodeId = 0;
 
@@ -65,7 +66,7 @@ export function normalizeToVNode(childVNode) {
 	}
 
 	if (type == 'object' || type == 'function') {
-		if (Array.isArray(childVNode)) {
+		if (isArray(childVNode)) {
 			return createElement(Fragment, null, childVNode);
 		}
 

src/diff/children.js

@@ -12,6 +12,7 @@ import { mount } from './mount';
 import { patch } from './patch';
 import { unmount } from './unmount';
 import { createInternal, getDomSibling } from '../tree';
+import { isArray } from '../util';
 
 /**
  * Update an internal with new children.
@@ -274,7 +275,7 @@ export function insertComponentDom(internal, nextSibling, parentDom) {
 export function toChildArray(children, out) {
 	out = out || [];
 	if (children == null || typeof children == 'boolean') {
-	} else if (Array.isArray(children)) {
+	} else if (isArray(children)) {
 		for (children of children) {
 			toChildArray(children, out);
 		}

src/diff/mount.js

@@ -19,6 +19,7 @@ import { createInternal, getParentContext } from '../tree';
 import options from '../options';
 import { ENABLE_CLASSES } from '../component';
 import { commitQueue } from './commit';
+import { isArray } from '../util';
 /**
  * Diff two virtual nodes and apply proper changes to the DOM
  * @param {import('../internal').Internal} internal The Internal node to mount
@@ -201,7 +202,7 @@ function mountElement(internal, dom, refs) {
 		} else if (newChildren != null) {
 			mountChildren(
 				internal,
-				Array.isArray(newChildren) ? newChildren : [newChildren],
+				isArray(newChildren) ? newChildren : [newChildren],
 				dom,
 				isNew ? null : dom.firstChild,
 				refs
@@ -409,7 +410,7 @@ function mountComponent(internal, startDom) {
 		if (renderResult.type === Fragment && renderResult.key == null) {
 			renderResult = renderResult.props.children;
 		}
-		if (!Array.isArray(renderResult)) {
+		if (!isArray(renderResult)) {
 			renderResult = [renderResult];
 		}
 	} else {

src/diff/patch.js

@@ -23,6 +23,7 @@ import { mountChildren } from './mount';
 import { Fragment } from '../create-element';
 import { ENABLE_CLASSES } from '../component';
 import { commitQueue } from './commit';
+import { isArray } from '../util';
 
 /**
  * Diff two virtual nodes and apply proper changes to the DOM
@@ -182,7 +183,7 @@ function patchElement(internal, vnode) {
 		if (oldHtml) dom.innerHTML = '';
 		patchChildren(
 			internal,
-			newChildren && Array.isArray(newChildren) ? newChildren : [newChildren],
+			newChildren && isArray(newChildren) ? newChildren : [newChildren],
 			dom
 		);
 	}
@@ -311,7 +312,7 @@ function patchComponent(internal, newVNode) {
 		if (renderResult.type === Fragment && renderResult.key == null) {
 			renderResult = renderResult.props.children;
 		}
-		if (!Array.isArray(renderResult)) {
+		if (!isArray(renderResult)) {
 			renderResult = [renderResult];
 		}
 	} else {

src/util.js

@@ -0,0 +1 @@
+export const isArray = Array.isArray;