WIP: one to multiple source maps #21

[DracoBlue]

I am trying to fix #21 and v8-to-istanbul: source-mappings from one to many files not yet supported

Approach:

0. v8-to-istanbul.js expects only one file of the sourcemap to be parsed at the same time
1. create a new method and walk through all source files of the sourcemap and reset state (this. sourceTranspiled and this.source) before

[bcoe]

👋 hey @DracoBlue, I apologize for not having had much time to look at this project lately. I'm excited that your'e looking into this.

[bcoe]

@DracoBlue still something you'd like to land, looks like a few tests are failing.

[DracoBlue]

@bcoe Yup. The test are failing because of the result dump. I am currently trying to get it working with a big webpack-based project. if this works properly I will add tests for my usecase and update the PR here.

[bcoe]

@DracoBlue very much appreciated 👏 we just landed some source-map related functionality in Node.js core, that's made me excited about dusting off these libraries ... they now work for edge-cases like ts-node.

[DracoBlue]

Nice!

I am currently struggling with those member variables. Hopefully I get this sorted within next days. Having v8 istanbul reporting for production sourcemap files would help me to end2end test our production build with little effort ;).

[SergeyPirogov]

@DracoBlue what is the progress with this? I struggling with the same issue.

[SergeyPirogov]

I've added these changes to my project and when trying to generate the report it's failing:

file: /home/sergey/Github/todomvc/examples/typescript-angular/js/Application.js error: TypeError: Cannot read property '0' of undefined
    at /home/sergey/Github/todomvc/examples/typescript-angular/node_modules/v8-to-istanbul/lib/v8-to-istanbul.js:66:75
    at async Promise.all (index 0)
    at async V8ToIstanbul.load (/home/sergey/Github/todomvc/examples/typescript-angular/node_modules/v8-to-istanbul/lib/v8-to-istanbul.js:46:39)
    at async Report.getCoverageMapFromAllCoverageFiles (/home/sergey/Github/todomvc/examples/typescript-angular/node_modules/c8/lib/report.js:69:9)
    at async Report.run (/home/sergey/Github/todomvc/examples/typescript-angular/node_modules/c8/lib/report.js:39:17)
    at async Object.exports.outputReport (/home/sergey/Github/todomvc/examples/typescript-angular/node_modules/c8/lib/commands/report.js:24:3)
    at async Object.exports.handler (/home/sergey/Github/todomvc/examples/typescript-angular/node_modules/c8/lib/commands/report.js:9:3)

[DracoBlue]

I am still struggling with the code, since some of these member variables are used elsewhere and it is not easy to emulate.

My ncc build does not highlight properly at all. So long I close this PR until I have time for this matter again.

[SergeyPirogov]

Will try to complete this