# ts-log

> Abstract logger TypeScript interface with a dummy logger that does nothing, useful for libraries.

Latest version **3.0.3** (published 2026-08-15) · MIT license · 0 weekly downloads

## Install

```sh
npm install ts-log
pnpm add ts-log
yarn add ts-log
bun add ts-log
```

## Health

**Score 70/100 (B)** — status: active.

Positive: has types; esm support; no vulnerabilities; recently updated; high maintenance score; high quality score.

Warnings: low downloads.

## Facts

| | |
|---|---|
| Version | 3.0.3 |
| Published | 2026-08-15 |
| First published | 2018-04-20 |
| Weekly downloads | 0 |
| License | MIT |
| TypeScript types | bundled |
| Module format | ESM + CommonJS |
| Node | >=20 |
| Dependencies | 0 |
| Unpacked size | 9 KB |
| Known vulnerabilities | 0 |
| Install scripts | no |
| GitHub stars | 12 |
| Author | Stagnation Lab |
| Maintainers | kallaspriit |
| Keywords | typescript, abstract, logger, console, dummy |

## Links

- npm: https://www.npmjs.com/package/ts-log
- Repository: https://github.com/kallaspriit/ts-log
- Homepage: https://github.com/kallaspriit/ts-log#readme
- Issues: https://github.com/kallaspriit/ts-log/issues
- npm.io page: https://npm.io/package/ts-log

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## Recent versions

- 3.0.3 (latest) — 2026-08-15
- 3.0.2 — 2026-04-28
- 3.0.1 — 2026-04-28
- 3.0.0 — 2026-03-18
- 2.2.7 — 2024-10-01
- 2.2.6 — 2024-10-01
- 2.2.5 — 2022-09-16
- 2.2.4 — 2021-10-27
- 2.2.3 — 2020-09-23
- 2.2.0 — 2020-09-23
- 2.1.4 — 2018-11-21
- 2.1.3 — 2018-09-05
- 2.1.2 — 2018-08-10
- 2.1.1 — 2018-08-10
- 2.1.0 — 2018-08-10
- … 6 more at https://npm.io/package/ts-log/versions

## README

# ts-log

[![CI](https://github.com/kallaspriit/ts-log/actions/workflows/ci.yml/badge.svg)](https://github.com/kallaspriit/ts-log/actions/workflows/ci.yml)
[![Downloads](https://img.shields.io/npm/dm/ts-log.svg)](http://npm-stat.com/charts.html?package=ts-log)
[![Version](https://img.shields.io/npm/v/ts-log.svg)](http://npm.im/ts-log)
[![License](https://img.shields.io/npm/l/ts-log.svg)](http://opensource.org/licenses/MIT)
[![StackGrit Score](https://img.shields.io/endpoint?url=https%3A%2F%2Ffleet-trout-946.convex.site%2Fapi%2Fbadge%2Fab080bce-08cf-4c0a-9ffa-c165470ad08d)](https://app.stackgrit.com/shared/b16e2501260e476597552a610a0b5542/reports/latest)

A zero-dependency TypeScript logger interface. Let library consumers choose their own logger — or stay silent by default.

## Installation

```
npm install ts-log
```

## Usage

Accept a `Logger` in your library's constructor, defaulting to `dummyLogger` (which does nothing):

```typescript
import { Logger, dummyLogger } from "ts-log";

class MyService {
  constructor(private readonly logger: Logger = dummyLogger) {}

  doWork() {
    this.logger.info("work started");
    // ...
    this.logger.debug("details", { foo: "bar" });
  }
}
```

Consumers can then pass in any compatible logger — or leave the default:

```typescript
// silent by default
const service = new MyService();

// or use the built-in console
const service = new MyService(console);

// or use pino, bunyan, winston, etc.
import pino from "pino";
const service = new MyService(pino());
```

## Logger Interface

The interface mirrors `console` — five methods, each accepting a message and optional parameters:

```typescript
interface Logger {
  trace(message?: any, ...optionalParams: any[]): void;
  debug(message?: any, ...optionalParams: any[]): void;
  info(message?: any, ...optionalParams: any[]): void;
  warn(message?: any, ...optionalParams: any[]): void;
  error(message?: any, ...optionalParams: any[]): void;
}
```

Any object matching this shape works — no adapters needed. This includes `console`, [pino](https://github.com/pinojs/pino), [bunyan](https://github.com/trentm/node-bunyan), [winston](https://github.com/winstonjs/winston), and most other Node.js loggers.

## Custom Logger

You can implement the interface directly for custom behavior:

```typescript
import fs from "node:fs";
import { Logger } from "ts-log";

class FileLogger implements Logger {
  private readonly fd: number;

  constructor(filename: string) {
    this.fd = fs.openSync(filename, "a");
  }

  trace(message?: any, ...params: any[]) {
    this.write("TRACE", message, params);
  }
  debug(message?: any, ...params: any[]) {
    this.write("DEBUG", message, params);
  }
  info(message?: any, ...params: any[]) {
    this.write("INFO", message, params);
  }
  warn(message?: any, ...params: any[]) {
    this.write("WARN", message, params);
  }
  error(message?: any, ...params: any[]) {
    this.write("ERROR", message, params);
  }

  private write(level: string, message: any, params: any[]) {
    fs.writeSync(this.fd, `${new Date().toISOString()} ${level} ${message} ${JSON.stringify(params)}\n`);
  }
}
```

## v3 Migration

v3 is a tooling modernization — the `Logger` interface and `dummyLogger` API are unchanged.

- Dual CJS/ESM package (via `exports` field).
- `"type": "module"` added to package.json.
- Minimum Node.js version is 20.
- Build output moved from `build/src/` to `dist/`.

## License

MIT

---
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