!@thi.ng/rstream-log

!npm downloads

> [!NOTE]
> This is one of 214 standalone projects, maintained as part
> of the @thi.ng/umbrella monorepo
> and anti-framework.
>
> 🚀 Please help me to work full-time on these projects by sponsoring me on
> GitHub. Thank you! ❤️

- About
- Status
- Support packages
- Related packages
- Installation
- Dependencies
- API
- Authors
- License

About

Structured, multilevel & hierarchical loggers based on @thi.ng/rstream.

This package provides extensible, multi-level & multi-hierarchy logging
infrastructure, with logged values transformable via
@thi.ng/transducers.
Several built-in transformers are provided.

The Logger class in this package implements the
@thi.ng/logger
ILogger interface and uses LogLevel enums to configure levels /
filtering. See that package for more details.

Status

STABLE - used in production

Search or submit any issues for this package

Support packages

- @thi.ng/rstream-log-file - File output handler for structured, multilevel & hierarchical loggers based on @thi.ng/rstream

Related packages

- @thi.ng/logger - Basis types for arbitrary & hierarchical logging

Installation

``bash
yarn add @thi.ng/rstream-log
`

ESM import:

`ts
import * as rslog from "@thi.ng/rstream-log";
`

Browser ESM import:

`html

`

JSDelivr documentation

For Node.js REPL:

`js
const rslog = await import("@thi.ng/rstream-log");
`

Package sizes (brotli'd, pre-treeshake): ESM: 749 bytes

Dependencies

- @thi.ng/api
- @thi.ng/checks
- @thi.ng/logger
- @thi.ng/rstream
- @thi.ng/strings
- @thi.ng/transducers

Note: @thi.ng/api is in _most_ cases a type-only import (not used at runtime)

API

Generated API docs

`ts tangle:export/readme.ts
import { LogLevel } from "@thi.ng/logger";
import { Logger, formatString, writeConsole } from "@thi.ng/rstream-log";

const logger = new Logger("main");
// or with min level
const logger = new Logger("main", LogLevel.DEBUG);
// or min level given as string
const logger = new Logger("main", "DEBUG");

// add console output w/ string formatter (a transducer)
// each logger instance has a rstream Stream instance
// allowing for downstream processing
logger.stream.transform(formatString()).subscribe(writeConsole());

logger.debug("hello world");
// [DEBUG] main: 2024-02-16T20:38:11.143Z hello world

logger.warn("eek");
// [WARN] main: 2024-02-16T20:38:11.144Z eek

// loggers can form hierarchies by creating/attaching child loggers
const child = logger.childLogger("child", LogLevel.INFO);

import { postWorker } from "@thi.ng/rstream";
// additionally send messages from this logger to worker
child.stream.subscribe(postWorker("log-worker.js"));

child.info("hi from submodule");
// [INFO] child: 2024-02-16T20:38:11.145Z hi from submodule
`

Authors

- Karsten Schmidt

If this project contributes to an academic publication, please cite it as:

`bibtex
@misc{thing-rstream-log,
title = "@thi.ng/rstream-log",
author = "Karsten Schmidt",
note = "https://thi.ng/rstream-log",
year = 2017
}
``

License

© 2017 - 2026 Karsten Schmidt // Apache License 2.0