log json with date and time format with winston node logger - node.js

Question

I am trying to log json with winston that includes a timestamp, I have the following configuration:
'use strict';
import * as winston from 'winston';
const LOG = !!process.env.LOG;
export const { error, info, debug } = winston.createLogger({
transports: [new winston.transports.Console()],
silent: process.env.NODE_ENV === 'test' && !LOG,
format: winston.format.combine(
winston.format.timestamp({
format: 'YYYY-MM-DD HH:mm:ss'
}),
winston.format.colorize({ all: true }),
winston.format.simple()
)
});
But it is logging messages like this:
info: connecting /closebanner {"timestamp":"2018-08-22 22:09:35"}
Only the timestamp is in json format and not the message.

Answer 1

You can use winston json formatter:
const { createLogger, format, transports } = require('winston');
const { combine, timestamp, json } = format;
const logger = createLogger({
format: combine(
timestamp({
format: 'YYYY-MM-DD HH:mm:ss'
}),
json(),
),
transports: [new transports.Console()]
})
So for example:
app.get('/', (req, res) => {
logger.info('request came');
logger.error({ "errorMessage": "something went wrong " })
return res.status(500).end();
})
app.listen(8080, () => {
logger.info('app started')
})
When You request localhost:8080 using GET HTTP method, it will result in:
{"message":"app started","level":"info","timestamp":"2018-08-23 00:56:48"}
{"message":"request came","level":"info","timestamp":"2018-08-23 00:56:54"}
{"message":{"errorMessage":"something went wrong"},"level":"error","timestamp":"2018-08-23 00:56:54"}
Please note that:
colorize will not work with JSON - check github discussion
format.simple() is not needed since it is just another type (string literal), more info in doc