Align properties of TsConfigJsonResolved with TypeScript's ParsedCommandLine

[JounQin]

See also ParsedCommandLine

https://github.com/microsoft/TypeScript/blob/fd3a84c3f0c80cb201c47399a055625f919a9b91/lib/typescriptServices.d.ts#L3168-L3178

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I'd like to replace parsing tsconfig.json from TypeScript to get-config more seamlessly.

It would be a BREAKING CHANGE.

[JounQin]

@privatenumber Hi, WDYT about this?

[privatenumber]

The first version of get-tsconfig used to return ParsedCommandLine by directly using TypeScript. (I moved the code to the FAQ.)

However, the output is very different and incompatible with most tools that expect a tsconfig JSON. For example, since the parsed version uses enums, all the values are converted to numbers. This makes it unusable for important tools (eg. esbuild).

It also makes preparations for compilation that may not be necessary in other tools. For example, it scans the disk and detects matched files. In tools like tsx, would be wasteful because the "compiled files" are detected via dependency tree.

I'm open to adding another util function that converts the static tsconfig.json JSON to the "parsed" one. Although, I'm skeptical how useful it would be.

The function names would probably need to be renamed to make more sense:

• Rename existing parseTsconfig to readTsconfig
• Add parseTsconfig(tsconfig: TsconfigObject): ParsedCommandLine

[JounQin]

@privatenumber

I'm working on a PR at import-js/eslint-plugin-import#2519 (comment), which aims to provide parsed tsconfig for resolvers, and also I have https://github.com/un-es/eslint-plugin-i#eslint-plugin-i to integrate with get-tsconfig.

See also import-js/eslint-import-resolver-typescript#179