digitUppercase (n) {
                let fraction = ['角', '分'];
                let digit = [
                    '零', '壹', '貳', '叄', '肆',
                    '伍', '陸', '柒', '捌', '玖'
                ];
                let unit = [
                    ['元', '萬', '億'],
                    ['', '拾', '佰', '仟']
                ];
                let head = n < 0 ? '欠' : '';
                n = Math.abs(n);
                let s = '';
                for (let i = 0; i < fraction.length; i++) {
                    s += (digit[Math.floor(n *
                        10 * Math.pow(10, i)) % 10] + fraction[i]).replace(/零./, '');
                }
                s = s || '整';
                n = Math.floor(n);
                for (let i = 0; i <
                    unit[0].length && n > 0; i++) {
                    let p = '';
                    for (let j = 0; j < unit[1].length && n > 0; j++) {
                        p = digit[n % 10] + unit[1][j] + p;
                        n = Math.floor(n / 10);
                    }
                    s = p.replace(/(零.)*零$/, '').replace(/^$/, '零') + unit[0][i] + s;
                }
                return head + s.replace(/(零.)*零元/, '元')
                    .replace(/(零.)+/g, '零')
                    .replace(/^整$/, '零元整');
            },