GeezerVison

Ping Sheetal Nandi (@sheetalkamat) - would be nice to get this reviewed, too;

Sheetal Nandi (@sheetalkamat) I've updated this to support showing a config when there's no config file, but didn't enable it in --b; it just doesn't make much sense there. The only options --b respects are a handful that it takes on the command line only; and if the intent was to question the contents of the configs --b reads to actually perform builds, since it reads more than 1 config, it still doesn't make too much sense (since the point of the flag is to print the config instead of actually running the build the config configures). The functions for pretty printing the options, however, are here if you determine that such output would be useful in the builder's verbose logs.

I tried to use this today but ran into a couple of issues. The first one's simple --showConfig doesn't appear in tsc --help as it should.

The second is that the PR doesn't appear to implement the feature as requested in #15213. I could be using it incorrectly, but my output only shows compilerOptions I've explicitly set myself in my tsconfig.json. I interpret "effective config" to mean "show me everything that's about to be used to compile, regardless of whether or not I set it", but that's not what I see.

Hmm, as is it contains everything less some things that are implied defaults/equivalent to their defaults. I suppose in that respect it makes more of a minimal config. But not doing that would be... Unfortunate. Because then we'd have to list every option. And there's a lot of options.

And there's a lot of options.

It's true, but that's exactly what I want to see. I'm not sure how else to easily discover what those defaults actually are. I could be off base here, but it looks to me like the documentation for tsconfig.json shows the implied default, but not the resolved one. I might want to extend something that has implied default values when unset, like typeRoots, but retain the existing values. Or I might want to diff my effective config to the effective config of a previous version to track down which new compiler options have influenced my program (I've had to do this the hard way before; it involved a lot of rather nasty console.log() calls in the TypeScript source). A diff can show me that in five seconds flat.

tsc --init prints with a ton of commented out defaults and help text.