Allow comments in tsconfig.json

[RehanSaeed]

Comments don't seem to be allowed in the tsconfig.json file. See this article for why it is ok according to Douglas Crockford to add them to json config files.

This is the error I get when adding comments to my tsconfig.json file:

var typescript = require("gulp-typescript");
var typeScriptProject = ts.createProject("tsconfig.json");

Process terminated with code 0.
> cmd.exe /c gulp -b "C:\Test\WebApplication1\WebApplication1" --color --gulpfile "C:\Test\WebApplication1\WebApplication1\Gulpfile.js" build-js
SyntaxError: Unexpected token /
    at Object.parse (native)
    at Function.createProject (C:\Test\WebApplication1\WebApplication1\node_modules\gulp-typescript\release\main.js:195:40)
    at Object.<anonymous> (C:\Test\WebApplication1\WebApplication1\Gulpfile.js:68:28)
    at Module._compile (module.js:456:26)
    at Object.Module._extensions..js (module.js:474:10)
    at Module.load (module.js:356:32)
    at Function.Module._load (module.js:312:12)
    at Module.require (module.js:364:17)
    at require (module.js:380:17)
    at Liftoff.handleArguments (C:\Test\WebApplication1\WebApplication1\node_modules\gulp\bin\gulp.js:116:3)
    at Liftoff.<anonymous> (C:\Test\WebApplication1\WebApplication1\node_modules\gulp\node_modules\liftoff\index.js:192:16)
    at module.exports (C:\Test\WebApplication1\WebApplication1\node_modules\gulp\node_modules\liftoff\node_modules\flagged-respawn\index.js:17:3)
Process terminated with code 8.
    at Liftoff.<anonymous> (C:\Test\WebApplication1\WebApplication1\node_modules\gulp\node_modules\liftoff\index.js:185:9)
    at C:\Test\WebApplication1\WebApplication1\node_modules\gulp\node_modules\liftoff\index.js:159:9
    at C:\Test\WebApplication1\WebApplication1\node_modules\gulp\node_modules\v8flags\index.js:99:14
    at C:\Test\WebApplication1\WebApplication1\node_modules\gulp\node_modules\v8flags\index.js:38:7
    at process._tickCallback (node.js:419:13)

[ivogabe]

I think this should be implemented in TypeScript first. If this would be implemented in gulp-typescript only, you cannot use the tsconfig file in VSCode for instance, whereas this configuration file was designed to be a universal config file. I'm not sure whether such issue has already been reported at the TypeScript repository. If not, you can report an issue there.

[RehanSaeed]

@ivogabe Thanks, I've raised a new issue on the official TypeScript project. Let's see what happens.

[jods4]

@ivogabe Time to reopen this issue I think!
TS 1.8 now includes support for comments in tsconfig.json.
Unfortunately we can't use them in combination with gulp-typescript because it does its own parsing based on JSON.parse, which does not support comments.

[aliok]

👍
I got the same problem. Running tsc works perfect with a commented tsconfig.json but not with gulp-typescript.

FYI, TS people just removed the JSON comments and then parsed the file.

See sarod/TypeScript@b60d88f

[jods4]

Most robust approach would be to call parseConfigFileTextToJson() if possible, I see it's exported (from the module it's defined in, at least).
Otherwise probably copy their code?

It's not as intuitive as you'd think, for instance it supports # as line comments.

[aliok]

Well, that solution I posted is changed a lot by the TS people while merging into TS.

This is their merged solution:
microsoft/TypeScript@3e63144

See the discussion:
microsoft/TypeScript#5450

[aliok]

Thanks for fixing the issue. Any plans about release?

[ivogabe]

Probably next week

[RehanSaeed]

@ivogabe Has this feature made it out yet?

[ivogabe]

It has been added in v2.12.1

[aliok]

@ivogabe Great!
Confirmed, it works.