Create a custom logger in TypeScript.

httpLogger.ts

// Put in src/middlewares/

import morgan, { StreamOptions } from "morgan";
import Logger from "../utils/logger";

const stream: StreamOptions = {
    write: message => Logger.http(message),
}

function skip():boolean {
    const env = process.env.NODE_ENV || "development";
    return env !== "development";
}
const morganMiddleWare = morgan(
    ":method :url :status :res[content-length] - :response-time ms",
    { stream, skip }
)

export default morganMiddleWare;

/*
use it in express as...
app.use(morganMiddleWare);
*/

logger.ts

import winston from "winston";

const logFileName:string = 'logs/error.log';

const levels = {
  error: 0,
  warn: 1,
  info: 2,
  http: 3,
  debug: 4,
}

const colors: winston.config.AbstractConfigSetColors  = {
  error: 'red',
  warn: 'yellow',
  info: 'green',
  http: 'magenta',
  debug: 'white',
}

function level() : string {
    const env: string | undefined = process.env.NODE_ENV || 'development';
    const isDevelopment = env === 'development';
    return isDevelopment ? 'debug' : 'warn';
}

winston.addColors(colors);

const format = winston.format.combine(
    winston.format.timestamp({ format: 'YYYY-MM-DD HH:mm:ss:ms' }),
    winston.format.colorize({ all: true }),
    winston.format.printf(info => `${info.timestamp} ${info.level}: ${info.message}`),
)

const transports: Array<any> = [
    new winston.transports.Console(),
    new winston.transports.File({
        filename: logFileName,
        level: 'error',
    }),
    new winston.transports.File({ filename: logFileName }),
];

const Logger: winston.Logger = winston.createLogger({
    level: level(),
    levels,
    format,
    transports
});

export default Logger;