nx tries to parse JSONC files as JSON which causes commands to fail

I created a “hello-world”-style NX repository using the following command:

npx create-nx-workspace isaacscript --preset=ts

After that, the only modification I made was to add more content to the extensions.json file.

After that, I ran the following command:

nx generate @nrwl/js:library --name=isaac-typescript-definitions --buildable --publishable --importPath="isaac-typescript-definitions"

It fails, with the following error message:

Cannot parse .vscode/extensions.json: ValueExpected in JSON at position 440

The “extensions.json” file is a JSONC file. JSONC is a format that supports comments and trailing commas. Thus, I believe that the error message is related to NX is trying to parse the JSONC file as a JSON file.

Since it is common for “extensions.json”, “settings.json”, and so on to contain JSONC features, this bug should be fixed!

[DesignByOnyx]

What sucks about this issue is that you run into very early. I had just set up my Nx workspace, made a couple changes to migrate existing/working tsconfigs, and then tried to run my first Nx command, and it failed with a really obscure error (see OP). When I visited the file, there were no visible errors (my editor shows errors in tsconfigs). This was not a pleasant “first taste” of Nx, and many others are likely to run into it. It’s an important issue because it affects new adopters of Nx, especially since Nx sells itself as “works with any project”.

[DesignByOnyx]

I just ran into this issue too. They are using the jsonc-parser, which has an option for allowTrailingComma (I don’t think jsonc allows trailing commas by default). The options are passed as the 3rd parameter here:

https://github.com/nrwl/nx/blob/master/packages/nx/src/utils/json.ts#L49

It would be nice if trailing commas were allowed by default, especially when reading tsconfig files.