currency.js 738 Bytes

 const digitsRE = /(\d{3})(?=\d)/g
 
 export function currency (value, currency, decimals) {
   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
 }