logger.ts

import { formatWithOptions } from 'util';
import winston, { Logform, format, transports } from 'winston';
import chalk, { ChalkInstance } from 'chalk';
import moment from 'moment';

const FORMAT_OPTIONS = {
  depth: null,
  maxArrayLength: null,
  breakLength: 120,
  colors: process.stdout.isTTY
};

export const LOG_LEVELS = {
  error: 0,
  warn: 1,
  notice: 2,
  info: 3,
  debug: 4,
  trace: 5
};

export const LOG_COLORS: Record<keyof typeof LOG_LEVELS, ChalkInstance> = {
  error: chalk.red,
  warn: chalk.yellow,
  notice: chalk.blue,
  info: chalk.green,
  debug: chalk.cyan,
  trace: chalk.magenta
};

let logLevel = process.env.LOG_LEVEL ?? 'info';
let complainLogLevel = false;
if (!(logLevel in LOG_LEVELS)) {
  logLevel = 'info';
  complainLogLevel = true;
}

const formatTimestamp = () => moment().format('YYYY-MM-DD hh:mm:ss').trim();

export let logger = winston.createLogger({
  levels: LOG_LEVELS,
  level: logLevel,
  transports: [
    new transports.Console()
  ],
  format: format.combine(
    format.printf((info: Logform.TransformableInfo) => {
      // @ts-ignore typescript pls
      let splat = info[Symbol.for('splat')];
      let formattedMessage = splat
        ? formatWithOptions(FORMAT_OPTIONS, info.message, ...splat)
        : formatWithOptions(FORMAT_OPTIONS, info.message);
      let moduleName = info.module ?? 'unknown';
      let level: string;
      if (info.level in LOG_LEVELS) {
        level = LOG_COLORS[<keyof typeof LOG_COLORS> info.level](info.level);
      } else {
        level = 'INVALID LOG LEVEL:' + info.level;
      }
      return `${formatTimestamp()} [${moduleName}/${level}] ${formattedMessage}`;
    })
  )
});

if (complainLogLevel) {
  forModule('logger').error('provided log level', process.env.LOG_LEVEL, 'is not valid, defaulting to', logLevel);
}

export function forModule(name: string) {
  return logger.child({ module: name });
}

export default forModule;