code: function commafy (num, options) {
    num = ('' + num).replace(/,/g, '')
    if (num) {
      var opts = baseExports.assign({ spaceNumber: 3, separator: ',' }, options)
      var optFixed = opts.fixed
      var result = (optFixed ? stringToNumber(num).toFixed(optFixed) : num).split('.')
      return result[0].replace(new RegExp('(?=(?!(\\b))(\\d{' + opts.spaceNumber + '})+$)', 'g'), opts.separator) + (result[1] ? '.' + result[1] : '')
    }
    return num
  }
docs: 千分位分隔符、小数点
  
  @param {String/Number} num 数值
  @param {Object} 参数 {spaceNumber: 分割位数(默认3), separator: 分隔符(默认,), fixed: 小数位数(默认null)}
  @return {String}