diff --git a/types/d3-dispatch/d3-dispatch-tests.ts b/types/d3-dispatch/d3-dispatch-tests.ts
index 4e8d2cfb31..b4f44ad4d2 100644
--- a/types/d3-dispatch/d3-dispatch-tests.ts
+++ b/types/d3-dispatch/d3-dispatch-tests.ts
@@ -47,12 +47,12 @@ undef = dispatch.on('unknown') as undefined;
 dispatch.on('bar', dispatch.on('bar')!);
 
 dispatch.call('foo');
-dispatch.call('foo', document.body);
-dispatch.call('foo', document.body, { a: 3, b: 'test' }, 1);
+dispatch.call('foo', document.body!);
+dispatch.call('foo', document.body!, { a: 3, b: 'test' }, 1);
 
 dispatch.apply('bar');
-dispatch.apply('bar', document.body);
-dispatch.apply('bar', document.body, [{ a: 3, b: 'test' }, 1]);
+dispatch.apply('bar', document.body!);
+dispatch.apply('bar', document.body!, [{ a: 3, b: 'test' }, 1]);
 
 dispatch.on('bar', null);
 
diff --git a/types/deku/deku-tests.ts b/types/deku/deku-tests.ts
index d123c7b8f7..d0467adead 100644
--- a/types/deku/deku-tests.ts
+++ b/types/deku/deku-tests.ts
@@ -24,7 +24,7 @@
 		})
 	}
 
-	let render = createApp(document.body)
+	let render = createApp(document.body!)
 
 	function main(state: any){
 		let vnode = view(state, (action: any) => main({ count: 0 }))
@@ -43,7 +43,7 @@
 		return element('div', { class: `size-${ props.size }` })
 	}
 
-	const render = createApp(document.body)
+	const render = createApp(document.body!)
 
 	render(element(App, { size: 'small' }))
 
@@ -82,11 +82,11 @@
 (function (){
 	const { createApp, element } = deku
 
-	let render: Function = createApp(document.body)
+	let render: Function = createApp(document.body!)
 
 	render(element('div'))
 
-	render = createApp(document.body, (action: any) => {
+	render = createApp(document.body!, (action: any) => {
 		render(element('div'))
 	})
 
diff --git a/types/downloadjs/downloadjs-tests.ts b/types/downloadjs/downloadjs-tests.ts
index 00bb5395ef..da110af46d 100644
--- a/types/downloadjs/downloadjs-tests.ts
+++ b/types/downloadjs/downloadjs-tests.ts
@@ -7,6 +7,6 @@ download(new Blob(['hello world']), 'dlTextBlob.txt', 'text/plain');
 
 download('/robots.txt');
 
-download(document.documentElement.outerHTML, 'dlHTML.html', 'text/html');
+download(document.documentElement!.outerHTML, 'dlHTML.html', 'text/html');
 download(new Blob(['hello world'.bold()]), 'dlHtmlBlob.html', 'text/html');
 download('/diff6.png');
diff --git a/types/i18next-browser-languagedetector/i18next-browser-languagedetector-tests.ts b/types/i18next-browser-languagedetector/i18next-browser-languagedetector-tests.ts
index eadfcea369..174a871b9f 100644
--- a/types/i18next-browser-languagedetector/i18next-browser-languagedetector-tests.ts
+++ b/types/i18next-browser-languagedetector/i18next-browser-languagedetector-tests.ts
@@ -19,7 +19,7 @@ const options: LngDetector.DetectorOptions = {
     cookieDomain: "myDomain",
 
     // optional htmlTag with lang attribute, the default is:
-    htmlTag: document.documentElement
+    htmlTag: document.documentElement!
 };
 
 i18next.use(LngDetector).init({
diff --git a/types/jquery.notify/jquery.notify-tests.ts b/types/jquery.notify/jquery.notify-tests.ts
index 1af31996a1..1d872e92fa 100644
--- a/types/jquery.notify/jquery.notify-tests.ts
+++ b/types/jquery.notify/jquery.notify-tests.ts
@@ -1,4 +1,4 @@
-let $container: JQueryNotifyWidget = $("<div style='display:none' class='noprint'><div></div></div>").appendTo(document.body).notify();
+let $container: JQueryNotifyWidget = $("<div style='display:none' class='noprint'><div></div></div>").appendTo(document.body!).notify();
 
 let notification: JQueryNotifyInstance = $container.notify(
 	"create",
diff --git a/types/jsdom/jsdom-tests.ts b/types/jsdom/jsdom-tests.ts
index c672580a63..24b136e5ad 100644
--- a/types/jsdom/jsdom-tests.ts
+++ b/types/jsdom/jsdom-tests.ts
@@ -17,7 +17,7 @@ function test_executing_scripts1() {
 </body>`);
 
     // The script will not be executed, by default:
-    dom.window.document.body.children.length === 1;
+    dom.window.document.body!.children.length === 1;
 }
 
 function test_executing_scripts2() {
@@ -26,14 +26,14 @@ function test_executing_scripts2() {
 </body>`, { runScripts: 'dangerously' });
 
     // The script will be executed and modify the DOM:
-    dom.window.document.body.children.length === 2;
+    dom.window.document.body!.children.length === 2;
 }
 
 function test_executing_scripts3() {
     const window = (new JSDOM(``, { runScripts: 'outside-only' })).window;
 
     window.eval(`document.body.innerHTML = "<p>Hello, world!</p>";`);
-    window.document.body.children.length === 1;
+    window.document.body!.children.length === 1;
 }
 
 function test_virtualConsole() {
@@ -74,7 +74,7 @@ function test_serialize() {
     dom.serialize() === '<!DOCTYPE html><html><head></head><body>hello</body></html>';
 
     // Contrast with:
-    dom.window.document.documentElement.outerHTML === '<html><head></head><body>hello</body></html>';
+    dom.window.document.documentElement!.outerHTML === '<html><head></head><body>hello</body></html>';
 }
 
 function test_nodeLocation() {
@@ -86,7 +86,7 @@ function test_nodeLocation() {
     );
 
     const document = dom.window.document;
-    const bodyEl = document.body; // implicitly created
+    const bodyEl = document.body!; // implicitly created
     const pEl = document.querySelector('p')!;
     const textNode = pEl.firstChild!;
     const imgEl = document.querySelector('img')!;
diff --git a/types/mark.js/mark.js-tests.ts b/types/mark.js/mark.js-tests.ts
index a979990521..2f4bb62d9a 100644
--- a/types/mark.js/mark.js-tests.ts
+++ b/types/mark.js/mark.js-tests.ts
@@ -3,7 +3,7 @@ import * as Mark from 'mark.js';
 /* test instance */
 const mark = new Mark(document.querySelectorAll('div'));
 const markBySelector = new Mark('div');
-const markByElement = new Mark(document.body);
+const markByElement = new Mark(document.body!);
 
 mark.mark('keyword');
 mark.mark('keyword', {
diff --git a/types/marko/marko-tests.ts b/types/marko/marko-tests.ts
index 623ad12e5f..e43f61d8b5 100644
--- a/types/marko/marko-tests.ts
+++ b/types/marko/marko-tests.ts
@@ -18,7 +18,7 @@ const template: Template = require('template.marko');
     // $ExpectType RenderResult
     template
         .renderSync({ name: 'Marko' })
-        .appendTo(document.body);
+        .appendTo(document.body!);
 
     createServer((req, res) => {
         res.setHeader('content-type', 'text/html');
@@ -30,12 +30,12 @@ const template: Template = require('template.marko');
         .render({ $global: { flags: ['mobile'] } })
         .then((result) => {
             // $ExpectType RenderResult
-            result.appendTo(document.body);
+            result.appendTo(document.body!);
         });
 
     template.render({}, (err: Error | null, result: RenderResult) => {
         // $ExpectType RenderResult
-        result.appendTo(document.body);
+        result.appendTo(document.body!);
     });
 };
 
diff --git a/types/mithril/test/test-api.ts b/types/mithril/test/test-api.ts
index 73e03edeae..66c026f47d 100644
--- a/types/mithril/test/test-api.ts
+++ b/types/mithril/test/test-api.ts
@@ -142,7 +142,7 @@ const FRAME_BUDGET = 100;
 		});
 	};
 
-	m.render(document.body, userInputs(users));
+	m.render(document.body!, userInputs(users));
 }
 
 ////////////////////////////////////////////////////////////////////////////////
@@ -246,7 +246,7 @@ const FRAME_BUDGET = 100;
 	};
 
 	// example 1
-	m.route(document.body, "/", {
+	m.route(document.body!, "/", {
 		"/": {
 			view() {
 				return m(Layout, m(Home));
@@ -260,7 +260,7 @@ const FRAME_BUDGET = 100;
 	});
 
 	// example 2
-	m.route(document.body, "/", {
+	m.route(document.body!, "/", {
 		"/": {
 			render() {
 				return m(Layout, m(Home));
@@ -285,7 +285,7 @@ const FRAME_BUDGET = 100;
 		},
 	};
 
-	m.route(document.body, "/", {
+	m.route(document.body!, "/", {
 		"/": {
 			render() {
 				return m(Anon1);
@@ -313,7 +313,7 @@ const FRAME_BUDGET = 100;
 		}
 	};
 
-	m.route(document.body, "/user/list", {
+	m.route(document.body!, "/user/list", {
 		"/user/list": {
 			onmatch: state.loadUsers,
 			render() {
@@ -330,7 +330,7 @@ const FRAME_BUDGET = 100;
 {
 	let progress = 0;
 
-	m.mount(document.body, {
+	m.mount(document.body!, {
 		view() {
 			return [
 				m("input[type=file]", { onchange: upload }),
@@ -396,7 +396,7 @@ const FRAME_BUDGET = 100;
 		deserialize: value => value
 	})
 	.then(svg => {
-		m.render(document.body, m.trust(svg));
+		m.render(document.body!, m.trust(svg));
 	});
 }
 
diff --git a/types/mithril/test/test-class-component.ts b/types/mithril/test/test-class-component.ts
index 0b70773c9e..44c81a8b56 100644
--- a/types/mithril/test/test-class-component.ts
+++ b/types/mithril/test/test-class-component.ts
@@ -112,7 +112,7 @@ class Comp4 implements ClassComponent<Comp4Attrs> {
 //
 // Test that all are mountable components
 //
-m.route(document.body, '/', {
+m.route(document.body!, '/', {
 	'/comp0': Comp0,
 	'/comp1': Comp1,
 	'/comp2': Comp2,
diff --git a/types/mithril/test/test-factory-component.ts b/types/mithril/test/test-factory-component.ts
index 6d0102fe38..b53619fbf1 100644
--- a/types/mithril/test/test-factory-component.ts
+++ b/types/mithril/test/test-factory-component.ts
@@ -148,7 +148,7 @@ function comp5(): Component<Comp4Attrs, Comp5State> {
 //
 // Test that all are mountable components
 //
-m.route(document.body, '/', {
+m.route(document.body!, '/', {
 	'/comp0': comp0,
 	'/comp1': comp1,
 	'/comp2': comp2,
diff --git a/types/mithril/test/test-misc.ts b/types/mithril/test/test-misc.ts
index 3f377fec60..548811247d 100644
--- a/types/mithril/test/test-misc.ts
+++ b/types/mithril/test/test-misc.ts
@@ -10,9 +10,9 @@ const params = parseQueryString('?id=123');
 
 const qstr = buildQueryString({id: 123});
 
-render(document.body, 'Hello');
-render(document.body, h('h1', 'Test'));
-render(document.body, [
+render(document.body!, 'Hello');
+render(document.body!, h('h1', 'Test'));
+render(document.body!, [
 	h('h1', 'Test'), "abc", null, 123, false, h('p', 'Vnode array'),
 	['a', 123, undefined, h('div', 'Nested')]
 ]);
diff --git a/types/mithril/test/test-route.ts b/types/mithril/test/test-route.ts
index 7f82c9fa40..63f10e510e 100644
--- a/types/mithril/test/test-route.ts
+++ b/types/mithril/test/test-route.ts
@@ -66,7 +66,7 @@ const routeResolver: RouteResolver<Attrs, RRState> & RRState = {
 	}
 };
 
-route(document.body, '/', {
+route(document.body!, '/', {
 	'/': component1,
 	'/test1': {
 		onmatch(args, path) {
diff --git a/types/redom/redom-tests.ts b/types/redom/redom-tests.ts
index 0ec18f6a59..83eb899c65 100644
--- a/types/redom/redom-tests.ts
+++ b/types/redom/redom-tests.ts
@@ -4,13 +4,13 @@ const el1: HTMLElement = redom.el('');
 const el2: HTMLElement = redom.el('p', 'Hello, World!', (el: HTMLElement) => { el.setAttribute('ok', '!'); });
 const el3: HTMLElement = redom.html('p', 2, { color: 'red' });
 
-redom.mount(document.body, el1);
-redom.mount(document.body, el2, el1);
-redom.unmount(document.body, el1);
+redom.mount(document.body!, el1);
+redom.mount(document.body!, el2, el1);
+redom.unmount(document.body!, el1);
 
 redom.setAttr(el3, 'ok', '!');
 redom.setAttr(el3, { ok: '!' });
 redom.setStyle(el3, { color: 'blue' });
 redom.setChildren(el1, [el2, el3]);
 
-redom.mount(document.body, redom.text('Hello, World!'));
+redom.mount(document.body!, redom.text('Hello, World!'));
diff --git a/types/webtorrent/webtorrent-tests.ts b/types/webtorrent/webtorrent-tests.ts
index 63a9647902..d8ffba389d 100644
--- a/types/webtorrent/webtorrent-tests.ts
+++ b/types/webtorrent/webtorrent-tests.ts
@@ -31,7 +31,7 @@ client.add(magnetURI, {}, torrent => {
                 a.href = url;
             }
             a.textContent = 'Download ' + file.name;
-            document.body.appendChild(a);
+            document.body!.appendChild(a);
         });
     });
 
diff --git a/types/yandex-maps/yandex-maps-tests.ts b/types/yandex-maps/yandex-maps-tests.ts
index 5c52936813..2406ef6cd6 100644
--- a/types/yandex-maps/yandex-maps-tests.ts
+++ b/types/yandex-maps/yandex-maps-tests.ts
@@ -23,7 +23,7 @@ const balloonLayout = ymaps.templateLayoutFactory.createClass(
 	{
 		build(this: ymaps.ILayout): void {
 			(<ymaps.layout.templateBased.Base> (<any> this.constructor).superclass).build.call(this);
-			this.getParentElement().children.item(0).children.item(0).appendChild((<any> this.getData()).properties.get("balloonContent"));
+			this.getParentElement().children.item(0)!.children.item(0)!.appendChild((<any> this.getData()).properties.get("balloonContent"));
 		}
 	}
 );