Typescript sourcemaps with Sentry

Setting up sourcemap support for TypeScript with Sentry requires careful configuration across multiple files. Getting this working properly took considerable effort, so here's the complete setup.

src/index.ts

Initialize Sentry with the RewriteFrames integration:

Sentry.init({
  dsn: SENTRY_DSN,
  tracesSampleRate: 1.0,
  release: process.env.HEROKU_SLUG_COMMIT,
  integrations: [
    new RewriteFrames({
      root: process.cwd(),
    }),
    new Sentry.Integrations.Http({ tracing: true }),
    new Tracing.Integrations.Postgres(),
  ],
});

The key detail is setting root: process.cwd(), which establishes the repo root directory. On Heroku, this resolves to /app.

tsconfig.json

{
  "compilerOptions": {
    "target": "ES2017",
    "module": "commonjs",
    "lib": ["es6", "es2017", "esnext.asynciterable"],
    "skipLibCheck": true,
    "outDir": "./build",
    "moduleResolution": "node",
    "noImplicitAny": true,
    "strictNullChecks": true,
    "strictFunctionTypes": true,
    "noImplicitThis": true,
    "noUnusedLocals": true,
    "noUnusedParameters": true,
    "noImplicitReturns": true,
    "noFallthroughCasesInSwitch": true,
    "allowSyntheticDefaultImports": true,
    "esModuleInterop": true,
    "emitDecoratorMetadata": true,
    "experimentalDecorators": true,
    "resolveJsonModule": true,
    "allowJs": true
  },
  "exclude": ["node_modules"],
  "include": ["./src/**/*.tsx", "./src/**/*.ts", "src/modules.d.ts"]
}

Note that outDir is set to ./build.

tsconfig.prod.json

Extend the base configuration with production-specific settings:

{
  "extends": "./tsconfig.json",
  "compilerOptions": {
    "sourceMap": true,
    "removeComments": true,
    "inlineSources": true,
    "sourceRoot": "/",
    "noEmitHelpers": true,
    "importHelpers": true
  }
}

The critical setting here is "sourceMap": true.

package.json

{
  "scripts": {
    "prebuild": "del ./build",
    "build": "tsc --project tsconfig.prod.json",
    "sentry-release": "sentry-cli releases files \"$HEROKU_SLUG_COMMIT\" upload-sourcemaps --url-prefix '~/app/build' ./build"
  }
}

The Critical Step

The sentry-release script is essential — it tells Sentry to prefix all assets with ~/app/build, enabling proper sourcemap resolution and debugging capabilities in production.