Morgan (node.js): Coloring status code (as in 'dev') while using custom format

Question

I am using morgan for logging in node.js.

I like the status code coloring provided in the predefined format mode 'dev', but I am using a custom format.

How can I get the same coloring as in 'dev' mode?

Per morgan documentation, dev format is the following :

 :method :url :status :response-time ms - :res[content-length]

When I use that it does not color :

// does not color
app.use(morgan(':method :url :status :response-time ms - :res[content-length]')); 

But when I use predefined 'dev' it does color!

app.use(morgan('dev'));

Answer 1

You can use chalkJS for coloring very easily.

import morgan from 'morgan';
import chalk from 'chalk'; // or you can use the require('chalk') syntax too

export const morganMiddleware = morgan(function (tokens, req, res) {
    return [
        '\n\n\n',
        chalk.hex('#ff4757').bold('🍄  Morgan --> '),
        chalk.hex('#34ace0').bold(tokens.method(req, res)),
        chalk.hex('#ffb142').bold(tokens.status(req, res)),
        chalk.hex('#ff5252').bold(tokens.url(req, res)),
        chalk.hex('#2ed573').bold(tokens['response-time'](req, res) + ' ms'),
        chalk.hex('#f78fb3').bold('@ ' + tokens.date(req, res)),
        chalk.yellow(tokens['remote-addr'](req, res)),
        chalk.hex('#fffa65').bold('from ' + tokens.referrer(req, res)),
        chalk.hex('#1e90ff')(tokens['user-agent'](req, res)),
        '\n\n\n',
    ].join(' ');
});

app.use(morganMiddleware);

Answer 2

Yes it cannot colourise your output to console by default.

You can either refer to this article which takes help of the 'chalk' module in order to colourise the output to console.

Or else what I did was I used the default 'dev' configuration and I added an extra config for my custom tokens which left the default dev output as it is. Something like this:

app.use(morgan('dev'));
app.use(morgan('auth_id - :userid user_email - :email'));

This will do what you are trying to do but, the second output of morgan will be in a newline.

Answer 3

@Adam Reis pointed in the really nice direction. I came up with this solution:

morgan.token('splitter', (req) => {
    return "\x1b[36m--------------------------------------------\x1b[0m\n";
});
morgan.token('statusColor', (req, res, args) => {
    // get the status code if response written
    var status = (typeof res.headersSent !== 'boolean' ? Boolean(res.header) : res.headersSent)
        ? res.statusCode
        : undefined

    // get status color
    var color = status >= 500 ? 31 // red
        : status >= 400 ? 33 // yellow
            : status >= 300 ? 36 // cyan
                : status >= 200 ? 32 // green
                    : 0; // no color

    return '\x1b[' + color + 'm' + status + '\x1b[0m';
});
server.use(morgan(`:splitter\x1b[33m:method\x1b[0m \x1b[36m:url\x1b[0m :statusColor :response-time ms - length|:res[content-length]`));

Here is the result: