Random Notes:

• ["HUF", "JPY", "TWD"] are currencies that do not use decimals - they should be treated as integers
• Why do we need this? Main reason is formatting (1.00), but the other is 1 cent rounding issues:
• in rails console, do 1.15 * 100

Frontend:

https://currency.js.org/

import * as currency from 'currency.js';

get trialPrice() {
    return currency(this.props.trial.price);
  }

  get subTotal() {
    return this.price.multiply(this.itemQuantity);
  }

 get total() {
    let total = this.subTotal
      .subtract(this.discountAmount.value)
      .add(this.tax.value)
      .add(this.shipping.value);
    if (total.value <= 0) return currency(0);
    if (this.api !== 'Stripe') return total;
    return total.value > STRIPE_MINIMUM_CHARGE ? total : currency(STRIPE_MINIMUM_CHARGE);
  }

store.lineItems.total.value

Backend:

https://github.com/RubyMoney/money

require 'money'

  def convert_to_money(input, currency_code)
    no_decimal_currencies = ["HUF", "JPY", "TWD"]
    # BigDecimal removes ruby 1 cent bug issues
    converted_input = no_decimal_currencies.include?(currency_code) ? input.to_i  : BigDecimal((input.to_f * 100).to_s).round(2).to_i
    Money.rounding_mode = BigDecimal::ROUND_HALF_UP
    Money.new(converted_input, currency_code)
  end