@selesterkft/express-logger

Simple wrapper for winston and morgan for use in Express webapps.

Installation

Install the package with yarn:

yarn add @selesterkft/express-logger

Usage

This package supports three levels of logging, in descending order of severity:

• logger.error()
• logger.info()
• logger.debug()

All of them are called with a single parameter which can be a simple string or a javascript object. Objects will be parsed to JSON. Log files will have a basic format: a JSON entry of any logging event per line.

For logging http calls, use logger.middleware() as an Express middleware.

import express from 'express';
import logger from '@selesterkft/express-logger';

const app = express();
// Note that we do call the middleware() function.
app.use(logger.middleware());

const PORT = 4000;

app.get('/', (req, res) => {
  res.send('Hello world!');
});

app.listen(PORT, () => {
  logger.info(`App is listening on ${PORT}.`);
});

import logger from '@selesterkft/express-logger';

export default function doSomething() {
  logger.error('Something was done!');
}

For logging request and response bodies (only meaningful in debug mode), use logger.bodyMiddleware() as a middleware. Do not call it, and make sure to use it after parsing the request body.

// ...
app.use(express.json());
app.use(logger.middleware());
app.use(logger.bodyMiddleware);
// ...

Log files

Log files will be written to the logs/ folder, so don't forget to add it to your .gitignore file.

# Logs
logs/

Console logging

Express-logger will read NODE_ENV to determine the current node environment, and, unless it is 'production' or 'test', will output the logs to the console. Be sure to set the node environment to 'production' when appropriate to suppress console logging.

Using Jest, for example, should automatically set the environment to 'test'.