Replace useRef<T | null> with useRef<T>

See DefinitelyTyped/DefinitelyTyped#38228 (comment)

Author: tkrotoff

examples/HTML5ConstraintValidationAPI/App.tsx

@@ -29,9 +29,9 @@ function hasErrors(errors: Errors) {
 }
 
 function Form() {
-  const email = useRef<HTMLInputElement | null>(null);
-  const password = useRef<HTMLInputElement | null>(null);
-  const passwordConfirm = useRef<HTMLInputElement | null>(null);
+  const email = useRef<HTMLInputElement>(null);
+  const password = useRef<HTMLInputElement>(null);
+  const passwordConfirm = useRef<HTMLInputElement>(null);
 
   const [errors, setErrors] = useState<Errors>({
     email: [],

examples/MaterialUI/App.tsx

@@ -65,8 +65,8 @@ function getInitialInputsState() {
 }
 
 function Form({ classes }: FormProps) {
-  const form = useRef<FormWithConstraints | null>(null);
-  const password = useRef<HTMLInputElement | null>(null);
+  const form = useRef<FormWithConstraints>(null);
+  const password = useRef<HTMLInputElement>(null);
 
   const [inputs, setInputs] = useState<InputsState>(getInitialInputsState());
   const [signUpButtonDisabled, setSignUpButtonDisabled] = useState(false);

examples/Password/App.tsx

@@ -39,8 +39,8 @@ async function isACommonPassword(password: string) {
 }
 
 function Form() {
-  const form = useRef<FormWithConstraints | null>(null);
-  const password = useRef<HTMLInputElement | null>(null);
+  const form = useRef<FormWithConstraints>(null);
+  const password = useRef<HTMLInputElement>(null);
 
   const [inputs, setInputs] = useState({
     email: '',

examples/PasswordWithoutState/App.tsx

@@ -6,8 +6,8 @@ import './index.html';
 import './style.css';
 
 function Form() {
-  const form = useRef<FormWithConstraints | null>(null);
-  const password = useRef<HTMLInputElement | null>(null);
+  const form = useRef<FormWithConstraints>(null);
+  const password = useRef<HTMLInputElement>(null);
 
   async function handleChange({ target }: React.ChangeEvent<HTMLInputElement>) {
     await form.current!.validateFields(target);

examples/PlainOldReact/App.tsx

@@ -39,9 +39,9 @@ function hasErrors(errors: Errors) {
 }
 
 function Form() {
-  const email = useRef<HTMLInputElement | null>(null);
-  const password = useRef<HTMLInputElement | null>(null);
-  const passwordConfirm = useRef<HTMLInputElement | null>(null);
+  const email = useRef<HTMLInputElement>(null);
+  const password = useRef<HTMLInputElement>(null);
+  const passwordConfirm = useRef<HTMLInputElement>(null);
 
   const [errors, setErrors] = useState<Errors>({
     email: [],

examples/ServerSideRendering/App.tsx

@@ -37,8 +37,8 @@ async function isACommonPassword(password: string) {
 }
 
 function Form() {
-  const form = useRef<FormWithConstraints | null>(null);
-  const password = useRef<HTMLInputElement | null>(null);
+  const form = useRef<FormWithConstraints>(null);
+  const password = useRef<HTMLInputElement>(null);
 
   const [inputs, setInputs] = useState({
     email: '',

examples/WizardForm/WizardFormStep1.tsx

@@ -9,7 +9,7 @@ interface Props {
 }
 
 export function WizardFormStep1(props: Props) {
-  const form = useRef<FormWithConstraints | null>(null);
+  const form = useRef<FormWithConstraints>(null);
 
   async function handleChange({ target }: React.ChangeEvent<HTMLInputElement>) {
     props.onChange(target);

examples/WizardForm/WizardFormStep2.tsx

@@ -12,7 +12,7 @@ interface Props {
 }
 
 export function WizardFormStep2(props: Props) {
-  const form = useRef<FormWithConstraints | null>(null);
+  const form = useRef<FormWithConstraints>(null);
 
   async function handleChange({ target }: React.ChangeEvent<HTMLInputElement>) {
     props.onChange(target);

examples/WizardForm/WizardFormStep3.tsx

@@ -13,7 +13,7 @@ interface Props {
 }
 
 export function WizardFormStep3(props: Props) {
-  const form = useRef<FormWithConstraints | null>(null);
+  const form = useRef<FormWithConstraints>(null);
 
   async function handleChange({
     target