货币filter

输入金额, 货币符号, 已经精度(小数点后保留的位数)

currency(12345, "￥", 2) ==> "￥12,345.00"

export function currency (value, currency, decimals) {
  const digitsRE = /(\d{3})(?=\d)/g
  value = parseFloat(value)
  if (!isFinite(value) || (!value && value !== 0)) return ‘‘
  currency = currency != null ? currency : ‘$‘
  decimals = decimals != null ? decimals : 2
  var stringified = Math.abs(value).toFixed(decimals)
  var _int = decimals
? stringified.slice(0, -1 - decimals)
: stringified
  var i = _int.length % 3
  var head = i > 0
? (_int.slice(0, i) + (_int.length > 3 ? ‘,‘ : ‘‘))
: ‘‘
  var _float = decimals
? stringified.slice(-1 - decimals)
: ‘‘
  var sign = value < 0 ? ‘-‘ : ‘‘
  return sign + currency + head +
_int.slice(i).replace(digitsRE, ‘$1,‘) +
_float
}