https://github.com/matrixai/js-logger
TypeScript/JavaScript Logger Library
https://github.com/matrixai/js-logger
logging structured-logging tracing
Last synced: 8 months ago
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TypeScript/JavaScript Logger Library
- Host: GitHub
- URL: https://github.com/matrixai/js-logger
- Owner: MatrixAI
- License: apache-2.0
- Created: 2021-02-14T23:38:36.000Z (about 5 years ago)
- Default Branch: staging
- Last Pushed: 2025-04-22T02:42:46.000Z (11 months ago)
- Last Synced: 2025-04-22T04:23:28.239Z (11 months ago)
- Topics: logging, structured-logging, tracing
- Language: TypeScript
- Homepage: https://polykey.com
- Size: 1.01 MB
- Stars: 1
- Watchers: 7
- Forks: 0
- Open Issues: 6
-
Metadata Files:
- Readme: README.md
- License: LICENSE
Awesome Lists containing this project
README
# js-logger
This library provides a JavaScript/TypeScript logger inspired by Python's
logger.
- Simple logging with default handlers supporting `console.log`,
`console.error`, and `process.stderr`.
- Fast, logging level checks or log filters are applied **before** log records
are created
- Complex log records properties support lazy evaluation, so they evaluated only
when they need to be rendered
- Flexible composition of loggers, handlers and formatters
- Custom formatting using template literals
- Supports structured logging through a JSON formatter
- Supports hierarchical logging through parent-child logger graph
- CI/CD tests on Linux, MacOS and Windows
- Zero runtime dependencies!
- Comprehensive continuous benchmarks in CI/CD
## Installation
```sh
npm install --save @matrixai/logger
```
## Usage
```ts
import Logger, { LogLevel, StreamHandler, formatting } from '@matrixai/logger';
const logger = new Logger('root', LogLevel.INFO, [
new StreamHandler(
formatting.format`${formatting.date}:${formatting.level}:${formatting.key}:${formatting.msg}:${formatting.data}`,
),
]);
logger.debug('Hello world', { a: { b: [123, 456] } });
logger.info('Hello world', { 123: { b: [123, 456] } });
logger.warn('Hello world', { lazy: () => 'string' });
logger.error('Hello world', formatting.format`my custom format`);
const loggerChild = logger.getChild('child');
loggerChild.info(
'Hello world',
{ 123: { b: [123, 456] } },
formatting.format`${formatting.keys}:${formatting.msg}:${formatting.data}`,
);
```
There's lots more options available in the source code. See the docs and see the
source code for more details.
## Development
Run `nix develop`, and once you're inside, you can use:
```sh
# install (or reinstall packages from package.json)
npm install
# build the dist
npm run build
# run the repl (this allows you to import from ./src)
npm run tsx
# run the tests
npm run test
# lint the source code
npm run lint
# automatically fix the source
npm run lintfix
```
### Docs Generation
```sh
npm run docs
```
See the docs at: https://matrixai.github.io/js-logger/
### Publishing
Publishing is handled automatically by the staging pipeline.
Prerelease:
```sh
# npm login
npm version prepatch --preid alpha # premajor/preminor/prepatch
git push --follow-tags
```
Release:
```sh
# npm login
npm version patch # major/minor/patch
git push --follow-tags
```
Manually:
```sh
# npm login
npm version patch # major/minor/patch
npm run build
npm publish --access public
git push
git push --tags
```