Replace defaultProps with default function parameters

As default props on function components are going to be deprecated in future release in favor of default function parameters (see: facebook/react#16210), I followed the recommendation. Note that default function parameters were actually already used (see `lockProps` for example)!

src/FocusGuard.js

@@ -11,20 +11,16 @@ export const hiddenGuard = {
   left: '1px',
 };
 
-const InFocusGuard = ({ children }) => (
+const InFocusGuard = ({ children = null }) => (
   <React.Fragment>
     <div key="guard-first" data-focus-guard data-focus-auto-guard style={hiddenGuard} />
     {children}
     {children && <div key="guard-last" data-focus-guard data-focus-auto-guard style={hiddenGuard} />}
   </React.Fragment>
 );
+
 InFocusGuard.propTypes = {
   children: PropTypes.node,
 };
 
-InFocusGuard.defaultProps = {
-  children: null,
-};
-
-
 export default InFocusGuard;

src/FreeFocusInside.js

@@ -14,8 +14,4 @@ FreeFocusInside.propTypes = {
   className: PropTypes.string,
 };
 
-FreeFocusInside.defaultProps = {
-  className: undefined,
-};
-
 export default FreeFocusInside;

src/Lock.js

@@ -19,11 +19,11 @@ const FocusLock = React.forwardRef(function FocusLockUI(props, parentRef) {
 
   const {
     children,
-    disabled,
-    noFocusGuards,
-    persistentFocus,
-    crossFrame,
-    autoFocus,
+    disabled = false,
+    noFocusGuards = false,
+    persistentFocus = false,
+    crossFrame = true,
+    autoFocus = true,
     allowTextSelection,
     group,
     className,
@@ -34,7 +34,7 @@ const FocusLock = React.forwardRef(function FocusLockUI(props, parentRef) {
     lockProps: containerProps = {},
     sideCar: SideCar,
 
-    returnFocus: shouldReturnFocus,
+    returnFocus: shouldReturnFocus = false,
     focusOptions,
 
     onActivation: onActivationCallback,
@@ -208,26 +208,4 @@ FocusLock.propTypes = {
   sideCar: any.isRequired,
 };
 
-FocusLock.defaultProps = {
-  children: undefined,
-  disabled: false,
-  returnFocus: false,
-  focusOptions: undefined,
-  noFocusGuards: false,
-  autoFocus: true,
-  persistentFocus: false,
-  crossFrame: true,
-  hasPositiveIndices: undefined,
-  allowTextSelection: undefined,
-  group: undefined,
-  className: undefined,
-  whiteList: undefined,
-  shards: undefined,
-  as: 'div',
-  lockProps: {},
-
-  onActivation: undefined,
-  onDeactivation: undefined,
-};
-
 export default FocusLock;

src/MoveFocusInside.js

@@ -21,7 +21,7 @@ export const useFocusInside = (observedRef) => {
   }, [observedRef]);
 };
 
-function MoveFocusInside({ disabled: isDisabled, className, children }) {
+function MoveFocusInside({ disabled: isDisabled = false, className, children }) {
   const ref = React.useRef(null);
   useFocusInside(isDisabled ? undefined : ref);
 
@@ -42,9 +42,4 @@ MoveFocusInside.propTypes = {
   className: PropTypes.string,
 };
 
-MoveFocusInside.defaultProps = {
-  disabled: false,
-  className: undefined,
-};
-
 export default MoveFocusInside;