raw reporter shouldn't output DqElements

[WilcoFiers]

While working on a new reporter I tried to run JSON.stringify() on the results of the raw reporter. Turns out that this is outputting DqElements, which can't be stringified after completing a run. Because the selectors are lazily constructed, and in order to construct them axe._selectorData is required, they can't be constructed after cleanup of axe._selectorData. To fix this we need to change the raw reporter to not output DqElement objects.

[jeeyyy]

Note:
Go thru results and any Dq element, toJson() or equivalent for selector

[jeeyyy]

@WilcoFiers - I was unable to find any DqElement in the raw report, so I could run a toJson on the same. Need more input.

[dbjorge]

We just hit this issue during development of https://github.com/Microsoft/axe-sarif-converter - the problematic elements are at JSON paths along the lines of root_raw_results[0].violations[0].node and root_raw_results[0].violations[0].any[0].relatedNodes[0].

One option for a low-churn fix that we tried out successfully would be updating the raw reporter to output JSON.parse(JSON.stringify(results)), rather than outputting results directly. I don't know that I'd recommend this, though, since DqElement.toJSON omits some properties from the original DqElement; I think it would be preferable for the output of the raw reporter to be as close as possible to the input that a new reporter library would be receiving (using the output of the raw reporter as test cases for the new reporter we're developing has been our primary use case for the raw reporter so far), so I think it might be better to do a more explicit step to replace the lazy properties in question with non-lazy ones in the existing finalization phase before the results get passed to reporters (https://github.com/dequelabs/axe-core/blob/develop/lib/core/utils/finalize-result.js).

[AutoSponge]

@WilcoFiers so, the test at https://github.com/dequelabs/axe-core/blame/320e63380189f507a32c99fd19619f3c6a161764/test/core/utils/dq-element.js#L35 is not a valid test for your case?

That may defeat the purpose of the raw reporter. Could I suggest a string reporter that uses a JSON.stringify({}, replacer) function to remove or otherwise normalize DQElements?