TimberWolf 2.0

An extremely lightweight dependency-free logger for Typescript

Installation

NPM:

npm install timberwolf --save

Yarn:

yarn add timberwolf --save

Example

import { logger } from "timberwolf";

logger.info("Hello World!"); 
// "[ INFO ] Hello World!"

logger.addMeta({
  user: "John Doe",
})

logger.debug('Hi John!')
// "[ DEBUG ] Hi John!", { user: "John Doe" }

logger.error('Something went wrong!', { error: 'John did it' }) 
// "[ ERROR ] Something went wrong!", { user: "John Doe", error: "John did it" }

## Usage

### Logging and levels

There are 6 log levels from `fatal` to `trace`.

```js
import { logger } from "timberwolf";

logger.fatal(message: string, metaData?: object);
logger.error(message: string, metaData?: object);
logger.warn(message: string, metaData?: object);
logger.info(message: string, metaData?: object);
logger.debug(message: string, metaData?: object);
logger.trace(message: string, metaData?: object);

Configuration

Set the logger

Timberwolf uses a single function to output all logs.

By default, the console logger is used, which outputs logs to console.log. This can be overwritten by using the setLogger method.

import { logger , Logger, LogLevel } from "timberwolf";

export const myLogger: Logger = (
  logLevel: LogLevel,
  msg: string,
  meta?: object,
) => {
  // Log however you want
};

// Set the logger to use myLogger
logger.setLogger(myLogger)

Setting the Log Level

The order of log priority is:

`` { FATAL: 1, ERROR: 2, WARN: 3, INFO: 4, DEBUG: 5, TRACE: 6, }

Everything below the LogLevel will not be pushed into the transport and not logged.

By default, the log level is set to `INFO` unless you provide a `LOG_LEVEL` environment variable, which will be parsed as a LogLevel.

Additionally, you can set the log level any time using the `setLogLevel` method.

```js
import { logger, LogLevel } from "timberwolf";

logger.setLogLevel(LogLevel.ERROR);

Adding meta data to every log

You may add any object of metadata to be added to the logs.

import { logger } from "timberwolf";

logger.addMeta({
  username: "Batman",
});

You may also clear the meta object.

import { logger } from "timberwolf";

logger.clearMeta();

The metadata will be spread over the metadata object for every subsequent log.

Meta masking

By default Timberwolf will mask sensitive keys in the metadata object. These are defined in the metaMask.ts file.

If you want to disable this, you can use the disableMetaMask method.

import { logger } from "timberwolf";

logger.disableMetaMask();

logger.info("Hello", {
  password: "pass123",
});
// "[ INFO ] Hello", { password: "********" }

logger.enableMetaMask();

logger.info("Hello", {
  password: "pass123",
});

Throwing errors

There is a convenience method to throw an error after logging it. This is available for all log levels.

import { logger } from "timberwolf";

logger.fatal("Oops").throw();
// Throws an error "Oops" after logging it

logger.fatal("Oops").throw("Oh no");
// Throws an error "Oh no" after logging "Oops"

Conditional logging

There is a convenience method when that only logs if the condition is truthy

import { logger } from "timberwolf";

logger.when(true).debug("Simon says");

logger.when(false).warn("Simon didn't say it");