@material-ui/core/esm/Modal/TrapFocus.js

React components that implement Google's Material Design.

/* eslint-disable consistent-return, jsx-a11y/no-noninteractive-tabindex */
import React from 'react';
import ReactDOM from 'react-dom';
import PropTypes from 'prop-types';
import warning from 'warning';
import ownerDocument from '../utils/ownerDocument';
import { useForkRef } from '../utils/reactHelpers';
/**
 * @ignore - internal component.
 */

function TrapFocus(props) {
  var children = props.children,
      _props$disableAutoFoc = props.disableAutoFocus,
      disableAutoFocus = _props$disableAutoFoc === void 0 ? false : _props$disableAutoFoc,
      _props$disableEnforce = props.disableEnforceFocus,
      disableEnforceFocus = _props$disableEnforce === void 0 ? false : _props$disableEnforce,
      _props$disableRestore = props.disableRestoreFocus,
      disableRestoreFocus = _props$disableRestore === void 0 ? false : _props$disableRestore,
      getDoc = props.getDoc,
      isEnabled = props.isEnabled,
      open = props.open;
  var ignoreNextEnforceFocus = React.useRef();
  var sentinelStart = React.useRef(null);
  var sentinelEnd = React.useRef(null);
  var nodeToRestore = React.useRef();
  var rootRef = React.useRef(null); // can be removed once we drop support for non ref forwarding class components

  var handleOwnRef = React.useCallback(function (instance) {
    // #StrictMode ready
    rootRef.current = ReactDOM.findDOMNode(instance);
  }, []);
  var handleRef = useForkRef(children.ref, handleOwnRef); // ⚠️ You may rely on React.useMemo as a performance optimization, not as a semantic guarantee.
  // https://reactjs.org/docs/hooks-reference.html#usememo

  React.useMemo(function () {
    if (!open) {
      return;
    }

    nodeToRestore.current = getDoc().activeElement;
  }, [open]); // eslint-disable-line react-hooks/exhaustive-deps

  React.useEffect(function () {
    if (!open) {
      return;
    }

    var doc = ownerDocument(rootRef.current); // We might render an empty child.

    if (!disableAutoFocus && rootRef.current && !rootRef.current.contains(doc.activeElement)) {
      if (!rootRef.current.hasAttribute('tabIndex')) {
        process.env.NODE_ENV !== "production" ? warning(false, ['Material-UI: the modal content node does not accept focus.', 'For the benefit of assistive technologies, ' + 'the tabIndex of the node is being set to "-1".'].join('\n')) : void 0;
        rootRef.current.setAttribute('tabIndex', -1);
      }

      rootRef.current.focus();
    }

    var contain = function contain() {
      if (disableEnforceFocus || !isEnabled() || ignoreNextEnforceFocus.current) {
        ignoreNextEnforceFocus.current = false;
        return;
      }

      if (rootRef.current && !rootRef.current.contains(doc.activeElement)) {
        rootRef.current.focus();
      }
    };

    var loopFocus = function loopFocus(event) {
      // 9 = Tab
      if (disableEnforceFocus || !isEnabled() || event.keyCode !== 9) {
        return;
      } // Make sure the next tab starts from the right place.


      if (doc.activeElement === rootRef.current) {
        // We need to ignore the next contain as
        // it will try to move the focus back to the rootRef element.
        ignoreNextEnforceFocus.current = true;

        if (event.shiftKey) {
          sentinelEnd.current.focus();
        } else {
          sentinelStart.current.focus();
        }
      }
    };

    doc.addEventListener('focus', contain, true);
    doc.addEventListener('keydown', loopFocus, true); // With Edge, Safari and Firefox, no focus related events are fired when the focused area stops being a focused area
    // e.g. https://bugzilla.mozilla.org/show_bug.cgi?id=559561.
    //
    // The whatwg spec defines how the browser should behave but does not explicitly mention any events:
    // https://html.spec.whatwg.org/multipage/interaction.html#focus-fixup-rule.

    var interval = setInterval(function () {
      contain();
    }, 50);
    return function () {
      clearInterval(interval);
      doc.removeEventListener('focus', contain, true);
      doc.removeEventListener('keydown', loopFocus, true); // restoreLastFocus()

      if (!disableRestoreFocus) {
        // In IE 11 it is possible for document.activeElement to be null resulting
        // in nodeToRestore.current being null.
        // Not all elements in IE 11 have a focus method.
        // Once IE 11 support is dropped the focus() call can be unconditional.
        if (nodeToRestore.current && nodeToRestore.current.focus) {
          nodeToRestore.current.focus();
        }

        nodeToRestore.current = null;
      }
    };
  }, [disableAutoFocus, disableEnforceFocus, disableRestoreFocus, isEnabled, open]);
  return React.createElement(React.Fragment, null, React.createElement("div", {
    tabIndex: 0,
    ref: sentinelStart,
    "data-test": "sentinelStart"
  }), React.cloneElement(children, {
    ref: handleRef
  }), React.createElement("div", {
    tabIndex: 0,
    ref: sentinelEnd,
    "data-test": "sentinelEnd"
  }));
}

process.env.NODE_ENV !== "production" ? TrapFocus.propTypes = {
  /**
   * A single child content element.
   */
  children: PropTypes.element.isRequired,

  /**
   * If `true`, the modal will not automatically shift focus to itself when it opens, and
   * replace it to the last focused element when it closes.
   * This also works correctly with any modal children that have the `disableAutoFocus` prop.
   *
   * Generally this should never be set to `true` as it makes the modal less
   * accessible to assistive technologies, like screen readers.
   */
  disableAutoFocus: PropTypes.bool,

  /**
   * If `true`, the modal will not prevent focus from leaving the modal while open.
   *
   * Generally this should never be set to `true` as it makes the modal less
   * accessible to assistive technologies, like screen readers.
   */
  disableEnforceFocus: PropTypes.bool,

  /**
   * If `true`, the modal will not restore focus to previously focused element once
   * modal is hidden.
   */
  disableRestoreFocus: PropTypes.bool,

  /**
   * Return the document to consider.
   * We use it to implement the restore focus between different browser documents.
   */
  getDoc: PropTypes.func.isRequired,

  /**
   * Do we still want to enforce the focus?
   * This prop helps nesting TrapFocus elements.
   */
  isEnabled: PropTypes.func.isRequired,

  /**
   * If `true`, the modal is open.
   */
  open: PropTypes.bool.isRequired
} : void 0;
/*

In the future, we should be able to replace TrapFocus with:
https://github.com/facebook/react/blob/master/packages/react-events/docs/FocusScope.md

```jsx
import FocusScope from 'react-dom/FocusScope';

function TrapFocus(props) {
  const {
    children
    disableAutoFocus = false,
    disableEnforceFocus = false,
    disableRestoreFocus = false,
    open,
  } = props;

  if (!open) {
    return children;
  }

  return (
    <FocusScope
      autoFocus={!disableAutoFocus}
      contain={!disableEnforceFocus}
      restoreFocus={!disableRestoreFocus}
    >
      {children}
    </FocusScope>
  );
}
```

*/

export default TrapFocus;