[Feature Request] Print project directory when diagnostics enabled

[AnyhowStep]

Search Terms

diagnostics, project directory

Suggestion

I have about 40+ sub-projects in a composite project right now and when building, it takes about 10 minutes.

It's hard to troubleshoot which projects are the bottleneck when I don't even know which projects are being built.

Enabling diagnostics only tells me how long a project took but doesn't tell me what that project is.

So, my feature request is to print the project directory when diagnostics is enabled.

---

At the moment, I've modified my own tsc.js,

//Find this line
reportTimeStatistic("Total time", programTime + bindTime + checkTime + emitTime);

//Replace with this snippet
reportTimeStatistic("Total time", programTime + bindTime + checkTime + emitTime);
if (program.getRootFileNames().length > 0) {
    const path = program.getRootFileNames()[0].replace(/\/[^/]+?\.[^.]+?$/, "");
    reportStatisticalValue("Project", (
        path.indexOf(program.getCurrentDirectory()) == 0 ?
            path.substr(program.getCurrentDirectory().length) :
            path
    ));
}

It works enough for me,

Files:                                      2944
Lines:                                    279749
Nodes:                                   1473021
Identifiers:                              417022
Symbols:                                  295304
Types:                                        73
Memory used:                             748010K
Assignability cache size:                      0
Identity cache size:                           0
Subtype cache size:                            0
I/O Read time:                             0.02s
Parse time:                                0.21s
Program time:                              0.84s
Bind time:                                 0.18s
printTime time:                            0.01s
Emit time:                                 0.01s
I/O Write time:                            0.01s
Total time:                                1.03s
Project:                  /src/app-route-handler

---

I don't really know much about the TypeScript API. There's probably a proper way to get this information but with my limited knowledge, I managed to hack that together.

Checklist

My suggestion meets these guidelines:

• This wouldn't be a breaking change in existing TypeScript/JavaScript code
• This wouldn't change the runtime behavior of existing JavaScript code
• This could be implemented without emitting different JS based on the types of the expressions
• This isn't a runtime feature (e.g. library functionality, non-ECMAScript syntax with JavaScript output, etc.)
• This feature would agree with the rest of TypeScript's Design Goals.

[AnyhowStep]

Thanks to that hack, I found out what gave me grief when it came to build times.

I had a generic function in a project that was used directly by about 15 sub projects (and indirectly by other sub projects). I forgot to add an explicit return type annotation to the generic function.

This project would take 3 seconds to build but the sub projects would take about 20-30s each.

The emitted .d.ts file for the generic function took up only 200+ lines but each line was thousands of characters long!

After adding the explicit return type annotation, the generic function became dozens of characters long and the ~15 sub projects now take 7-10s each.

Total time saved was ~5 minutes on cold builds. So, I cut the build time in half by adding one line of code.

Screenshots of the .d.ts, before and after, here,
typescript-eslint/typescript-eslint#730

[AnyhowStep]

https://youtu.be/wpgKd-rwnMw?t=3748

Seems like the experimental version was outputting the name of projects it was building,

Building compiler ...
Building services ...

That would actually be super helpful if I can have that, too, without hacking tsc.js

[elibarzilay]

👍 --- I ran into this too, with

tsc -b -f --diagnostics compiler