How to use the xterm/src/common/buffer/CellData.CellData function in xterm

private getLineAsHTML (y: number, start: number, end: number): string {
        let html = '<div>'
        let lastStyle: string|null = null
        const line = (this.xterm.buffer.getLine(y) as any)._line
        const cell = new CellData()
        for (let i = start; i &lt; end; i++) {
            line.loadCell(i, cell)
            const fg = this.getHexColor(cell.getFgColorMode(), cell.getFgColor(), this.configService.store.terminal.colorScheme.foreground)
            const bg = this.getHexColor(cell.getBgColorMode(), cell.getBgColor(), this.configService.store.terminal.colorScheme.background)
            const style = `color: ${fg}; background: ${bg}; font-weight: ${cell.isBold() ? 'bold' : 'normal'}; font-style: ${cell.isItalic() ? 'italic' : 'normal'}; text-decoration: ${cell.isUnderline() ? 'underline' : 'none'}`
            if (style !== lastStyle) {
                if (lastStyle !== null) {
                    html += ''
                }
                html += `<span style="${style}">`
                lastStyle = style
            }
            html += line.getString(i) || ' '
        }
        html += '</span></div>'
        return html