Minified code gives wrong line of code

Hi there,

I tried out the transformer and it works perfect in dev mode, so first: thanks a lot for that 😃 👍

Nonetheless: When not running in debug mode and let the code crash somewhere, the lines and colums are a little bit off.

Steps to reproduce (I forked git clone https://github.com/cbrevik/react-native-typescript-starter and did some changes to illustrate the problem):

https://github.com/hffmnn/react-native-typescript-starter
cd react-native-typescript-starter
git checkout --track origin/feature/ts_map
yarn
yarn bundle:ios:release

Open the iOS project with Xcode and press run.I modified:

• index.tsx to crash after 3 seconds
• the Xcode scheme to run in Release mode
• the Xcode Build Phase to not start the bundling.

The app will crash. Press continue until Xcode spits out something useful like:

Exception: Can't find variable: doSomethingStupid, stack:
<unknown>@365:441
callTimer@31:626
callTimers@31:1010
value@29:2893
<unknown>@29:832
value@29:2294
value@29:804

Run

./symbolicate.js ios/main.jsbundle.map 365 441

Expected: The output is: <some_user_specific_path>/react-native-typescript-starter/src/index.tsx:19

Experienced: The output is: <some_user_specific_path>/react-native-typescript-starter/src/index.tsx:13 (Note the difference in the line number)

To verify that it has something to do with dev mode or maybe minify:

• Delete the app from simulator!!!
• Clean the Xcode project!!!
• Run yarn bundle:ios:dev
• Rerun the application

Experienced: The output is (as expected): <some_user_specific_path>/react-native-typescript-starter/src/index.tsx:19

I already verified, that the generated sourcemaps for JS based projects (so e.g. a default RN project) work in dev and release mode, so this issue is only valid for how we create the source maps for TS.

I already checked the docs for source-map (https://www.npmjs.com/package/source-map) but could not find any hint, why that should not work.

Any ideas what else might be the problem?

[ds300]

Metro issue over here https://github.com/facebook/metro-bundler/issues/10 🤞

[ds300]

Cool beans. I’m gonna close this. Thanks @quincycs and @skellock