How to use the roosterjs-editor-core.Keys.BACKSPACE function in roosterjs-editor-core

/**
 * AutoLink edit feature, provides the ability to automatically convert text user typed or pasted
 * in hyperlink format into a real hyperlink
 */
export const AutoLink: GenericContentEditFeature = {
    keys: [Keys.ENTER, Keys.SPACE, Keys.CONTENTCHANGED],
    shouldHandleEvent: cacheGetLinkData,
    handleEvent: autoLink,
};

/**
 * UnlinkWhenBackspaceAfterLink edit feature, provides the ability to convert a hyperlink back into text
 * if user presses BACKSPACE right after a hyperlink
 */
export const UnlinkWhenBackspaceAfterLink: GenericContentEditFeature = {
    keys: [Keys.BACKSPACE],
    shouldHandleEvent: hasLinkBeforeCursor,
    handleEvent: (event, editor) => {
        event.rawEvent.preventDefault();
        removeLink(editor);
    },
};

function cacheGetLinkData(event: PluginEvent, editor: Editor): LinkData {
    return event.eventType == PluginEventType.KeyDown ||
        (event.eventType == PluginEventType.ContentChanged && event.source == ChangeSource.Paste)
        ? cacheGetEventData(event, 'LINK_DATA', () => {
              // First try to match link from the whole paste string from the plain text in clipboard.
              // This helps when we paste a link next to some existing character, and the text we got
              // from clipboard will only contain what we pasted, any existing characters will not
              // be included.
              let clipboardData =

getTagOfNode,
    isNodeEmpty,
    splitBalancedNodeRange,
    unwrap,
    wrap,
} from 'roosterjs-editor-dom';

const QUOTE_TAG = 'BLOCKQUOTE';
const STRUCTURED_TAGS = [QUOTE_TAG, 'LI', 'TD', 'TH'].join(',');

/**
 * UnquoteWhenBackOnEmpty1stLine edit feature, provides the ability to Unquote current line when
 * user press BACKSPACE on first and empty line of a BLOCKQUOTE
 */
export const UnquoteWhenBackOnEmpty1stLine: ContentEditFeature = {
    keys: [Keys.BACKSPACE],
    shouldHandleEvent: (event, editor) => {
        let childOfQuote = cacheGetQuoteChild(event, editor);
        return childOfQuote && isNodeEmpty(childOfQuote) && !childOfQuote.previousSibling;
    },
    handleEvent: splitQuote,
};

/**
 * UnquoteWhenEnterOnEmptyLine edit feature, provides the ability to Unquote current line when
 * user press ENTER on an empty line of a BLOCKQUOTE
 */
export const UnquoteWhenEnterOnEmptyLine: ContentEditFeature = {
    keys: [Keys.ENTER],
    shouldHandleEvent: (event, editor) => {
        let childOfQuote = cacheGetQuoteChild(event, editor);
        let shift = event.rawEvent.shiftKey;

export const OutdentWhenShiftTab: ContentEditFeature = {
    keys: [Keys.TAB],
    shouldHandleEvent: (event, editor) =>
        event.rawEvent.shiftKey && cacheGetListElement(event, editor),
    handleEvent: (event, editor) => {
        setIndentation(editor, Indentation.Decrease);
        event.rawEvent.preventDefault();
    },
};

/**
 * MergeInNewLine edit feature, provides the ability to merge current line into a new line when user press
 * BACKSPACE at beginning of a list item
 */
export const MergeInNewLine: ContentEditFeature = {
    keys: [Keys.BACKSPACE],
    shouldHandleEvent: (event, editor) => {
        let li = cacheGetElementAtCursor(editor, event, 'LI');
        let range = editor.getSelectionRange();
        return li && range && isPositionAtBeginningOf(Position.getStart(range), li);
    },
    handleEvent: (event, editor) => {
        let li = cacheGetElementAtCursor(editor, event, 'LI');
        if (li.previousSibling) {
            editor.runAsync(() => {
                let br = editor.getDocument().createElement('BR');
                editor.insertNode(br);
                editor.select(br, PositionType.After);
            });
        } else {
            toggleListAndPreventDefault(event, editor);
        }