Add detailed field to __buildSalesTaxContext

[maktouch]

This is so we can generate Canadian invoices with this library. In Canada, you need to list individual amounts of taxes on the invoice because they are filed to different government bodies.

It passes jshint, and no tests are broken (this is purely additive).

Hope we can get this merged.

Merci!

[coveralls]

Coverage increased (+0.4%) to 85.843% when pulling 7c6c9f2 on wisercpd:master into e7063d8 on valeriansaliou:master.

[adrai]

Isn't this the same as just calling additionally i.e. SalesTax.getSalesTax("CA", "SK") yourself?

[maktouch]

It isn't, no. Without this change, it'll output like

{
  type: 'gst+qst',
  rate: 0.14975,
  area: 'national',
  exchange: 'consumer',
  charge: { direct: true, reverse: false }
}

With this change, it'll output

{
  type: 'gst+qst',
  rate: 0.14975,
  detailed: { gst: 0.05, qst: 0.09975 },
  area: 'national',
  exchange: 'consumer',
  charge: { direct: true, reverse: false }
}

While technically 0.14975 is the good rate, in the invoicing part, it needs to be split.

For getAmountWithSalesTax, it looks like this

SalesTax.getAmountWithSalesTax("CA", "QC", 100).then(console.log);

{
  type: 'gst+qst',
  rate: 0.14975,
  price: 100,
  total: 114.97500000000001,
  area: 'national',
  exchange: 'consumer',
  charge: { direct: true, reverse: false },
  detailed: [
    { type: 'gst', rate: 0.05, amount: 5 },
    { type: 'qst', rate: 0.09975, amount: 9.975000000000001 }
  ]
}

It's so we can use the same library for generating invoice + calculating total.

[valeriansaliou]

Thanks for your PR. It's agreed on my side, I'll make some reworks and integrate your PR work in a separate commit.

[valeriansaliou]

I've integrated your changes manually, coded unit tests as well as added documentation in the README about this new "details" object.

Changes relative to your PR:

• Renamed "detailed" into "details"
• Moved the "details" object type to an array type

(See the README for more on how to use it.)

[valeriansaliou]

Closing this as this has been integrated. Thanks a lot for your work! Pushing a new release on NPMJS now, all tests are green.

[valeriansaliou]

Released v2.2.0. Thanks a ton @maktouch ! https://github.com/valeriansaliou/node-sales-tax/blob/master/CHANGELOG.md#220-2020-06-12

[maktouch]

Thanks to you @valeriansaliou. Big fan of Crisp btw.

Cheers.