GoLang Money

GoLang library to make working with money safer, easier, and fun!

	- No dependencies - No anaemic model - JSON formatter - SQL driver - Localized formatter(s)
Money Value Object	“If I had a dime for every time I’ve seen someone use FLOAT to store currency, I’d have $999.997634” — Bill Karwin In short: You shouldn’t represent monetary values by a float. Wherever you need to represent money, use this Money value object.

package main
import (
    "fmt"
    "github.com/radical-app/money"
)
func main() {
    fiveEur := money.EUR(500) // see list of all currencies
    tenEur, err := fiveEur.Add(fiveEur)
    fmt.Print(err)
    zeroEur, err := tenEur.Subtract(tenEur)
    fmt.Print(err)
    zeroEur.IsZero() // true
    anotherFiveEur,err := zeroEur.Add(fiveEur)
    fmt.Print(err)
    fiveEur.IsEquals(anotherFiveEur) // true
    fmt.Print(fiveEur.String()) // EUR 500 for beautiful formatter see below 
}

.Forge and .Parse

Money from Int and only if you really-really-really need …Forge from Float

go
usd312 := money.USD(312)
usd312, err := money.Forge(312, "USD")

go usd312 := money.FloatUSD(3.12) usd312, err := money.ForgeFloat(3.12, "USD")

More .Parse() from string

.Parse() is the opposite of .String()

go
usd312, err := money.Parse("USD 312")
usd312.String() // "USD 312"

go eur312, err := money.ParseWithFallback("312", "EUR") // this uses EUR because the string has it eur312, err := money.ParseWithFallback("EUR 312", "JPY") // not suggested solution use ParseWithFallback if you have to deal with multiple currencies money.DefaultCurrencyCode="JPY" jpy312, err := money.Parse("312")

example at parse_test.go

Marshal/UnMarshal Custom Formatter

Custom Marshaller from and to Json

go
json.Marshal(money.EUR(123))

will produce the simplified json for money.DTO:

json {"amount":123,"currency":"EUR","symbol":"€","cents":100}

and

go m := &Money{} json.Unmarshal([]byte('{"amount":123,"currency":"EUR","symbol":"€","cents":100}'), m)

will produce the money.EUR(123)

example at marshal_test.go

.String()

money.EUR(123).String() // "EUR 123"

.Display() beautiful money depending based on locale

import "github.com/radical-app/money/moneyfmt"
import "github.com/radical-app/money"
moneyfmt.Display(money.EUR(123400), "ru") // € 1 234
moneyfmt.Display(money.EUR(123456), "ru") // € 1 234,56
moneyfmt.Display(money.EUR(123456), "it") // € 1.234,56
moneyfmt.Display(money.EUR(123400), "it") // € 1.234
moneyfmt.Display(money.EUR(123456), "en") // € 1,234.56
moneyfmt.Display(money.EUR(123456), "jp") // € 1,234.56
moneyfmt.Display(money.EUR(123456), "zh") // € 1,234.56

example at moneyfmt/moneyfmt_test.go

SQL custom field support driver

Is possible to use in mysql the field as int or varchar or if you really really need decimal(13,4)

_, err := db.Exec("insert into blablabla int, string, decimal (?,?,?)",
  money.EUR(123).Int64(),
  money.EUR(123).String(),
  money.EUR(123).Float()
)

and the Scan during a select is auto-magically done:

rows.Scan(&moneyStoredAsInt64,
  &moneyStoredAsString,
  &moneyStoredAsFloat
)

Real example: driver_integration_test.go

Limit

The biggest amount you can store in is 92.233.720.368.547.758,07 the math.MaxInt64 / currency.cents