Support for custom TSConfig path

[iamakulov]

Hey,

Is there a chance ESBuild would support specifying a custom path to tsconfig.json/jsconfig.json?

Prior art

TypeScript supports passing a custom path to tsconfig.json using the -p (or --project) CLI parameter:

tsc -p tsconfig.tests.json

Use cases

My use-case: the project I’m working on uses ESBuild for development and webpack for production. To run ESBuild, we have to replace one package with a custom mock. We do this through tsconfig.json’s paths:

{
    "compilerOptions": {
        "paths": {
            ...
            "linaria": ["./environment/linaria-esbuild-mock.ts"]
        },
    }
}

However, putting this into the primary tsconfig.json results in a bad DX. (E.g., Ctrl+clicking linaria imports now leads to the mock instead of the original file.) It would be great if we had tsconfig.esbuild.json with necessary overrides – and were able to point ESBuild to use it.

Other use-cases: A few projects I saw used tsconfig.test.json for custom test configs (e.g., for custom include/exclude configuration).

[evanw]

I see why this would be useful, but I'm having trouble figuring out what the right implementation would be. There can be many tsconfig.json files spread throughout a directory tree. Does this force-override all of them? Just one of them? Is it only a fallback if no tsconfig.json file is found? Does there need to be some way of configuring different overrides for different directories?

[iamakulov]

I see why this would be useful, but I'm having trouble figuring out what the right implementation would be. There can be many tsconfig.json files spread throughout a directory tree. Does this force-override all of them? Just one of them? Is it only a fallback if no tsconfig.json file is found? Does there need to be some way of configuring different overrides for different directories?

I’d follow the TS implementation:

Using tsconfig.json or jsconfig.json

• By invoking tsc with no input files, in which case the compiler searches for the tsconfig.json file starting in the current directory and continuing up the parent directory chain.
• By invoking tsc with no input files and a --project (or just -p) command line option that specifies the path of a directory containing a tsconfig.json file, or a path to a valid .json file containing the configurations.

— Source

Which means:

• tsconfig.jsons in child directories are ignored. (E.g., see this test project: here, both root.ts and a/a.ts are compiled to ES5 – even though a/tsconfig.json specifies "target": "ESNext".)
• If you specify an explicit tsconfig.json path, it will override any automatically detected tsconfig.json

[evanw]

Thanks for finding this information! After reading that, I agree that following the TypeScript implementation does sound like the right thing to do.

[seriouscoderone]

I have a related issue, where I want to bundle the tsconfig compilerOptions.paths as "nodeModules", but it only looks at the package.json https://github.com/aws/aws-cdk/blob/b2037d3b1a63715f71587681c84a5fd34be939a7/packages/%40aws-cdk/aws-lambda-nodejs/lib/util.ts#L91

[uglycoyote]

I'm not clear on whether this issue was closed because it was implemented, or denied? Is there currently a way to esbuild to set a custom tsconfig path? I could not find anything in the command line options list.

I'm in this situation becuase I'm combining esbuild and another bundler on the same repo. Currently i have tsconfig's target property set to es5, but my esbuild doesn't know how to transform a bunch of the features used in the codebase to es5, forcing me to switch it to es6. But using es6 breaks my existing build with the other bundler, so I would like to keep using what works (es5) when building with that bundler, and use es6 for esbuild.

EDIT: nevermind, sorry I didn't realize at first that it was linking a revision above which fixed this.

For future reference of anyone ending up here first:

The option is:

  --tsconfig=...            Use this tsconfig.json file instead of other ones

and it's here in the docs https://esbuild.github.io/api/#tsconfig