msftBidAdapter member bid param is serialized as "[object Object]" in the endpoint query string

[GautierDeMo]

Hello, I hope you're doing great.
It's my first time submitting an issue and it's related to a use case at work, so I hope the description is okay.

The msft bid adapter supports two ways of identifying inventory: placement_id, or the pair member + inv_code. The second one cannot work in its current implementation.

Steps to reproduce

Configure an ad unit with the member / inv_code pair:

{
  bidder: 'msft',
  params: { member: 12345, inv_code: 'my_inventory_code' }
}

Run an auction and inspect the outgoing request to ib.adnxs.com.

Expected

https://ib.adnxs.com/openrtb2/prebidjs?member_id=12345&eqt=1

Actual

https://ib.adnxs.com/openrtb2/prebidjs?member_id=[object%20Object]&eqt=1

The request still succeeds, so nothing is logged — you just never get a bid.

Root cause

modules/msftBidAdapter.js, in formatRequest():

const memberId = ((bidderRequest?.bids) || []).find(bid => bid.params && bid.params.member && isNumber(bid.params.member));
if (memberId) {
  endpointUrl += (endpointUrl.indexOf('?') === -1 ? '?' : '&') + 'member_id=' + memberId;
}

Array.prototype.find returns the matching element, not the value inspected by the predicate.

Suggested fix

const memberId = ((bidderRequest?.bids) || []) .find((bid) => isNumber(bid.params?.member))?.params.member;

Additional issue: documentation inconsistency

While looking into this, a second inconsistency surfaced on the same parameter. isBidRequestValid requires member to be a number:

(typeof params.member === 'number' && isNotEmptyString(params?.inv_code))

But modules/msftBidAdapter.md documents it as a String and uses member: "123" in every example.

Platform details

Reproduced on Prebid.js 10.14.0. The same code is still present on master today, so the issue should still apply on 11.29.0

[jsnellbaker]

@GautierDeMo I'm sorry but are you sure you're looking at the current root project's master branch?
https://github.com/prebid/Prebid.js/blob/master/modules/msftBidAdapter.js#L456

This issue was present in 10.14.0, but it was fixed in the next release 10.15.0 (see #14076).

In the current version 11.29.0, the fix is still there and it still appears to be appending the member integer value correctly to the endpoint URL.

Please confirm.