Add new option "node-option"

[juergba]

Description

Currently Mocha is parsing its own options, plus Node and V8 options as well. Mocha has to recognize those foreign options in order to pass them to a newly spawned child-process.

Mocha's options are defined in yargs/yargs-parser, whereas Node/V8 options:

• are not white-listed
• Node: compared with process.allowedNodeEnvironmentFlags, which contains most but not all flags.
• V8: compared against a beautiful regex, otherwise v8[_-] has to be prepended.

This Mocha/Node hybrid parsing has some disadvantages:

• maintenance overhead
• some options can't be forwarded at all, eg. --prof, --require
• Mocha's option object gets polluted with invalid camelCased Node/V8 options
• Mocha can't print a warning in case of incorrect user input (typos)
• we have bugs in parsing of our own kebab-case options, which are difficult to fix with the current yargs-parser configuration

Description of the Change

Mocha should not have to check/process any Node/V8 flags, but simply parse and hand them over to Node.
So we add a new flag --node-option/ -n:

• array:
  • -n require=glob -n unhandled-rejections=strict or
  • -n require=glob,unhandled-rejections=strict
• no checks or processing, Mocha just hands the option over to Node by spawning a new child-process
• no merging: the two solutions are independent
• optional: remove current Mocha/Node hybrid solution on mid-term

in addition:

• prevent double parsing when bin/mocha is the entry point
• remove package esm special handling. This package is abandoned and not supported in Mocha v9
• remove gc check and deprecation warning. This V8 option doesn't exist anymore

[outsideris]

👍🏼

[outsideris]

To clear, can we specify name should be without -- nor --v8-?

[juergba]

I added the -- info. I prefer to not mention --v8- as this is a Mocha specific quirk and may be confusing.

[outsideris]

How about no leading "--" or "--v8-"

[juergba]

I haven't added the --v8- part, see comment above.