Missing report configuration defaultSummarizer

[miyasudokoro]

• Version: all
• Platform: all

There is a poorly-documented feature of the HTML Istanbul reporters (html, lcov, html-spa) called "defaultSummarizer". It would be nice if c8 could pass through this configuration option so it can be used.

I am willing to create a pull request for this issue myself.

Below is my documentation of what "defaultSummarizer" does from my pull request to @web/test-runner.

---

For some reporters, you can change the summary and hierarchy of reported files using the option defaultSummarizer.

• pkg
  • The default setting
  • Lists every subdirectory path on the main index page
  • Shows the summary of the files in each subdirectory
  • You must click into each subdirectory to see files
• nested:
  • Displays nested file structure, like in your operating system or IDE
  • Shows a deep summary of all the contents of each directory
  • You must click through the directory structure to each file
• flat:
  • All files are in one flat list
  • No directory-based summaries
  • There is only one page of results

Example HTML report structures:

Actual file structure:

• js
  • a.js
  • controller
  • b.js
  • manager
    • factory
    • c.js

pkg:

• js
  • a.js
• js/controller
  • b.js
• js/controller/manager/factory
  • c.js

nested:

• a.js
• controller
  • b.js
  • manager
  • factory
    • c.js

flat:

• a.js
• controller/b.js
• controller/manager/factory/c.js

[ericmorand]

If you feel like changing for another v8-driven code coverage tool, you can give One Double Zero a try. I just tested and it passes through any reporter options that it receives:

{
  "sources": [
    "./src/main/{.,!(target)/**}/*.ts"
  ],
  "reporters": [
    "html",
    "text"
  ],
  "reporterOptions": {
    "html": {
      "defaultSummarizer": "nested"
    }
  }
}

It is worth noting that the reporterOptions is not documented, which will be fixed: https://gitlab.com/nightlycommit/one-double-zero-documentation/-/issues/2

Note that I didn't know about that option and I have to thank you for that: the nested layout is the one I've been dreaming of ever since I've started using istanbul. 🙏