throws an error if the extends resolves to a JS file

[dylang]

Hi!

This code looks for require.resolve result - and only if that's not found does it try path.join(extendsPath, 'tsconfig.json').

The problem is what if require.resolve resolves to an index.js file. Then we try using that instead of path.join(extendsPath, 'tsconfig.json').

Then we try to read the JSON file. But it's JS not JSON, so we throw an error.

Example:

"extends": "@company/tsconfig"

@company/tsconfig package.json:

"main": "./src/index.js"

@company/tsconfig tsconfig.json

{
  // normal tsconfig.json
}

To resolve this we should do the resolving closer to how TypeScript does it. In this case, it would never resolve a .JS file, only .json. Perhaps if the filename is not .json we then attempt path.join(extendsPath, 'tsconfig.json').

[privatenumber]

Is this a real issue you're encountering?

It currently throws if not a valid JSON:

get-tsconfig/tests/specs/extends.spec.ts

Lines 22 to 34 in 58a696c

	test('invalid json', async () => {
	const fixture = await createFixture({
	'file.ts': '',
	'tsconfig.empty.json': 'require("fs")',
	'tsconfig.json': tsconfigJson({
	extends: './tsconfig.empty.json',
	}),
	});
	expect(() => getTsconfig(fixture.path)).toThrow('Failed to parse JSON');
	await fixture.cleanup();
	});

[dylang]

Yes - it throws if it's not valid JSON, but what I'm hoping for is that it prioritizes using the tsconfig.json in that path instead of the index.js.

I'm running into this when using tsx in our monorepo. We have a company-standard tsconfig package that has /tsconfig.json and a main pointing to /src/index.js.

TypeScript automatically uses the /tsconfig.json so we use extend: "company-tsconfig-package-name".

A potential workaround for us is to use extend: "company-tsconfig-package-name/tsconfig.json" but that would be a breaking change over many repos that I'm hoping to avoid.

[privatenumber]

Gotcha.

Do you mind opening a PR with a failing test case?

[dylang]

Failing test created.

BTW - the test framework throws an error but passes if the test JS doesn't compile. 😅

[privatenumber]

BTW - the test framework throws an error but passes if the test JS doesn't compile. 😅

What does this mean?