How to make CouponParams dynamic

Question

I have been working in PHP and I have done this easily in that but currently passing certain code to Go but having some issues.

This below is the parameters definition with go package for stripe

params := &stripe.CouponParams{
            Duration:         stripe.String(c.Duration),
            DurationInMonths: stripe.Int64(c.DurationInMonths),
            //PercentOff:       stripe.Float64(c.PercentOff),
            AmountOff:      stripe.Int64(c.AmountOff),
            Currency:       stripe.String(strings.ToLower(c.Currency)), //ISO code for the currency
            ID:             stripe.String(c.ID),
            MaxRedemptions: stripe.Int64(c.MaxRedemptions),
            //Name:           stripe.String(c.Name),
            AppliesTo: &stripe.CouponAppliesToParams{
                Products: c.AppliesTo.Products,
            },
            CurrencyOptions: map[string]*stripe.CouponCurrencyOptionsParams{
                //"eur": {AmountOff: stripe.Int64(9000)},
                "jpy": {AmountOff: stripe.Int64(12000)},
            },
        }

in PHP i would just have an array and i could manipulate it easily but with GO and my low knowledge i am currently stuck. Is there a way to make this conditionally? I have a few fields obligatory but there are few combinations that i'll need to make.

if c.Name != "" {//c is the struct from json body similar to the stripe but used with a validator
        //add it
    }