[Bug]: getLowestRate() doesn't account for difference currencies

[pauldraper]

Software Version

Language Version

Operating System

What happened?

getLowestRate() gives a bad result with different currencies, e.g. mixing CAD and USD sometimes chooses a numerically lower USD even if CAD quote is better.

I can't imagine any case where this is desirable behavior.

easypost-node/src/utils/util.js

Line 76 in 4f75889

getLowestRate(rates, carriers = null, services = null) {

What was expected?

Not sure, but the existence of getLowestRate() is a footgun.

Sample Code

No response

Relevant logs

No response

[nwithan8]

Hello, thank you for reaching out! We are triaging the issue currently. Do you perhaps have any logs you could share to help us reproduce the issue, specifically how you retrieved a combination of USD and non-USD rates?

[Harrison-Burgess]

Hey, what I did to produce this was creating a shipment
const shipmentData = { to_address: toAddress, from_address: fromAddress, parcel: await easypost.Parcel.create({ weight: getLineItemWeight(productWithQty), }), options: { currency: "USD", }, mode, };

shipment = await easypost.Shipment.create(shipmentData);
Where the addresses were from 2 different countries
This requested rates where we preferred them in USD. Some of the carriers didn't seem to work for the currency option though and still gave us back rates in the local currency.
const lowestRate = shipment.lowestRate([ "UPS", "CanadaPost", "FedExDefault", "USPSReturns", ]);

[Justintime50]

Hey @Harrison-Burgess, thanks for providing additional details. This particular issue sounds like it could be better solved at the API level as this client library's function behaved correctly based on its intended use-case - it can only determine the lowest rate with good data. With that said, you can reach our support team at [email protected] and describe the perceived bug to them. They'll work with our internal teams if possible to correct this so the carrier (if possible) can return currencies in the requested type. I will note that per our documentation, the currency option does state that only carriers that allow conversion will respect the shipment option of defining an explicit currency, if I had to guess, I assume CanadaPost does not at present, though it's possible that could change if requested.

As this issue happens at the API level, I'm going to close this issue since we do not intend to support currency conversion directly in our client libraries.