Typescript compilation is very slow when I use a tsconfig.json file

Question

When I run tsc with a project file (tsconfig.json) it takes a very long time (>1 minute) to finish. When I specify the same arguments on the command line or in an arguments file it finishes within seconds. This happens on Mac OS with typescript 2.7.2

This is the tsconfig.json that I use:

{
  "compilerOptions": {
    "target": "es2017",
    "module": "commonjs",
    "outDir": "dist", 
    "rootDir": "src",  
    "sourceMap": true
  }
}

When I time it using the time command I get the following result:

> time tsc --diagnostics -p tsconfig.json

Files:           38
Lines:        34429
Nodes:       157429
Identifiers:  52565
Symbols:      50844
Types:        12929
Memory used: 86147K
I/O read:     0.02s
I/O write:    0.01s
Parse time:   0.64s
Bind time:    0.44s
Check time:   1.91s
Emit time:    0.19s
Total time:   3.19s

real    2m20.611s
user    0m34.914s
sys     1m11.042s

It takes more than 2 minutes.

When I create an arguments file that looks like this:

--target es2017 --module commonjs --outDir dist --sourcemap

And time the command:

> time tsc --diagnostics @args src/*

Files:           38
Lines:        34429
Nodes:       157429
Identifiers:  52565
Symbols:      50844
Types:        12929
Memory used: 83773K
I/O read:     0.00s
I/O write:    0.00s
Parse time:   0.52s
Bind time:    0.24s
Check time:   1.10s
Emit time:    0.09s
Total time:   1.96s

real    0m2.259s
user    0m3.568s
sys     0m0.133s

Now it only takes 2 seconds, but I don't expect to see a significant difference, because I run typescript with the exact same options. Am I overlooking something?

Answer 1

If you have a nested directory structure, it should be src/**/* and not src/*

or use tsc @args --sourceRoot src