Type CommentJSONValue object properties

[felixhaeberle]

Tell us about your environment

I'm running this inside a vscode extension to parse the extensions.json

• Node Version: 18.16.1
• comment-json Version 4.2.3

Please show your use case / code slices / code link that could reproduce the issue

I want to have the returned value of parse correctly typed. It should return an json with recommendations as string[], but I can't get it to work.

let extensions: CommentJSONValue<{ recommendations: string[] }> |  undefined // doesn't work
extensions = parse(fs.readFileSync(extensionsJsonPath, "utf8"))
extensions?.recommendations?.includes("example.extension") || false // doesn't work

What did you expect to happen?

I want to have the recommendations typed correctly.
Thank you for your help!!

[stevebeauge]

In a project I'm working on, I had to parse tsconfig.json file, which can contains comments. The purpose of my project was to sync ts references and paths in a monorepo.

This library lacks strong typing support (or at least I didn't understood how to). What I did:

import { assign, CommentArray, CommentObject, parse as jsonCParse, stringify } from "comment-json";

type Reference = Partial<CommentObject> & {
    path: string;
};

type CompilerOptions = Partial<CommentObject> & {
    paths?: Record<string, CommentArray<string>>;
};

// Only the actual nodes I need
type TSConfigWithComments = Partial<CommentObject> & {
    references?: Reference[];
    compilerOptions?: CompilerOptions;
};

const tsConfigFile = await readFileAsync(projectData.tsConfigFile);

const tsConfig = jsonCParse(tsConfigFile) as TSConfigWithComments; // The only required cast here
if (tsConfig === undefined) {
    throw new Error(`Error parsing ${projectData.tsConfigFile}`);
}

if (!tsConfig.references) { // create property if not present
    assign(tsConfig, { references: [] });
}
if (!tsConfig.references) { // Actually useless, but makes TS know the references is not undefined (strictNullChecks enabled)
    throw new Error("references should be defined");
}
tsConfig.references.push({ path: someppath; }) // Add reference node

// Ensure compilerOptions.path is present
if (!tsConfig.compilerOptions) {
    assign(tsConfig, { compilerOptions: { paths: {} } });
}
if (!tsConfig.compilerOptions?.paths) {
    assign(tsConfig.compilerOptions, { paths: {} });
}
// Makes TS know it's not undefined
if (!tsConfig.compilerOptions?.paths) {
    throw new Error("compilerOptions.path should be defined");
}
tsConfig.compilerOptions.paths[`${someName}/*`] = new CommentArray(`${somePath}/src/*`);

const newJson = stringify(tsConfig, undefined, 2);

Not sure if it's the proper way to handle it, but maybe it can helps?

[felixhaeberle]

@stevebeauge Thanks! Will look into it.