reqheaders does not work when using an undefined requestBody

[josephearl]

Please avoid duplicates

• I checked all open bugs and none of them matched my problem.

Reproducible test case

https://github.com/josephearl/nock-reqheaders-repro

Nock Version

13.3.7

Node Version

v18.17.1

TypeScript Version

N/A

What happened?

When creating a request matcher and using reqheaders, these do not work when setting an undefined requestBody:

mock.get('/some/path', undefined, {
  reqheaders: { 'HEADER1': 'value1', 'HEADER2': 'value1' }
}).reply(200);

Strangely if you use null for the requestBody it does work - but null is not allowed by the TypeScript types which specificy requestBody must be undefined | RequestBody and the RequestBody type does not include null in its union.

Expected is that when using undefined for a requestBody the reqheaders matching still works.

See https://github.com/josephearl/nock-reqheaders-repro/tree/main for a reproducer.

NB: the all open bugs link (https://github.com/nock/nock.js/issues?q=is%3Aissue+is%3Aopen+label%3Abug) in your issue template leads to a 404 - because it is pointing to an old repo name nock.js

Would you be interested in contributing a fix?

• yes

[gr2m]

NB: the all open bugs link (https://github.com/nock/nock.js/issues?q=is%3Aissue+is%3Aopen+label%3Abug) in your issue template leads to a 404 - because it is pointing to an old repo name nock.js

thanks, fixed 👍

[mikicho]

@gr2m

This is because we ignore the interceptor's headers:

nock/lib/interceptor.js

Lines 68 to 74 in f4d1b15

	this.reqheaders = common.headersFieldNamesToLowerCase(
	scope.scopeOptions.reqheaders || {},
	true,
	)
	this.badheaders = common.headersFieldsArrayToLowerCase(
	scope.scopeOptions.badheaders || [],
	)

What's the expected behavior? Should we merge the headers? Do the interceptor's headers take precedence? vice-versa?

P.S: @josephearl I think it worked on null because it failed to match the body.

[gr2m]

I don't know out of hand, I'd have to digg into it as well. I'd look at tests first to see if the behavior might be covered