I'm unable to create working custom transformer

[react-native 0.23][windows][android] I’m currently struggling to make typescript sourcemaps work with react-native. As advised in https://github.com/facebook/react-native/issues/393#issuecomment-173247497, I have created transformer:

var transformer = require('react-native/packager/transformer');
var fs = require("fs");

module.exports = function (data, callback) {
    if (data.filename.indexOf("index.android.js") !== -1) {
        callback({
            code: data.sourceCode,
            map: JSON.parse(fs.readFileSync("./index.android.js.map").toString()),
            filename: data.filename
        })
    } else {
        transformer(data, callback);
    }
};

and when I’m executing react-native start --transformer <absolute path to this transformer after reaload js:

here is repro:

• clone https://github.com/krtr/native-repro
• npm install
• react-native run-android
• react-native start --transformer <absolute path to custom transformer
• tap reload js in phone/emulator

in case you want recreate sourcemaps tsc --target es6 --jsx react index.android.tsx (npm install typescript -g if you dont have typescript installed)

[alloy]

Here’s a custom transformer that sets up a pipeline that does TypeScript -> JS -> Babel transformation and all the source-map mangling required: https://github.com/artsy/emission/compare/93ab096089c3d07040511e070cb0585e66cccec2...5c6728b7058eac6a8fbd4353cd98e9f91a58ff99

[krtr]

@frogcjn Your custom transformer works great to me 🎉