Stampy

Stampy injects TypeScript file and line information at compile time. Runtime log events carry only a compact numeric call-site ID; a build manifest maps that ID back to the original source, even after bundling or minification.

Stamp every log with where it came from.

import { log } from "@cheruvian/stampy";

log.info("server listening", { port: 3000 });

Install Stampy and compile with stampy in place of tsc:

npm install @cheruvian/stampy typescript
npx stampy -p tsconfig.json

By default, development builds include readable source coordinates:

[src/server.ts:3:1] server listening { port: 3000 }

When NODE_ENV=production, calls contain and print only the compact symbol:

[#1n75gti] server listening { port: 3000 }

Override that behavior with --location full to always retain readable locations, or --location id to always use compact symbols. --location auto is the default.

The emitted call is equivalent to:

log.__emit("info", 3579214182, "server listening", { port: 3000 });

<outDir>/stampy-manifest.json contains the reverse mapping:

{
  "version": 1,
  "calls": {
    "3579214182": {
      "file": "src/server.ts",
      "line": 3,
      "column": 1,
      "level": "info"
    }
  }
}

Options:

stampy -p tsconfig.json
        --manifest path/to/manifest.json
        --module @cheruvian/stampy
        --location auto|full|id
        --console

Use --console to migrate or guard code that forgets the logger import. The transform adds its own collision-safe import and maps calls as follows:

console.log, console.info  -> info
console.debug              -> debug
console.warn               -> warn
console.error              -> error

Other console APIs such as table, dir, time, and trace retain their native behavior. Interception is opt-in because a locally shadowed variable named console cannot always be distinguished from the global in isolated transforms.

The transform only rewrites debug, info, warn, and error calls on the log named import from the configured module. Aliased imports are supported.