@evojs/logger

Smart logger for nodejs

Usage example

Set global configuration

import { Callsite, Logger, Level, Record } from '@evojs/logger';

const accessLogFileStream = createWriteStream(accessLogFile, { flags: 'a' });
const errorLogFileStream = createWriteStream(errorLogFile, { flags: 'a' });

Logger.configure({
  name: 'app',
  formats: [
    `{{ date | date }} {{ level | uppercase }}{{ name | name }} {{ args | message }}<-|->{{ callsite | file }}`,
    'json',
  ],
  pipes: {
    uppercase(text: string): string {
      return text.toUpperCase();
    },
    date(date: number): string {
      return new Date(date).toISOString();
    },
    name(name: string): string {
      return name ? ` <${name}>` : '';
    },
    message(args: any[]): string {
      return args
        .map((x) =>
          typeof x === 'string' ? x : x instanceof Error ? x.stack : inspect(x, false, null, false),
        )
        .join('\n');
    },
    file({ source, line, column }: Callsite = {}): string {
      return [source, line, column].filter(Boolean).join(':');
    },
  },
  handler(record: Record): void {
    const [customOutput, jsonOutput] = record.messages();
    // 2 formats => 2 outputs
    if (!errorLevels.includes(record.level)) {
      process.stdout.write(customOutput + '\n');
      accessLogFileStream.write(jsonOutput + '\n');
    } else {
      process.stderr.write(customOutput + '\n');
      errorLogFileStream.write(jsonOutput + '\n');
    }
  },
});

Changing separator mask

import { Logger, Log } from '@evojs/logger';

Log.separator = '<=!=>';

Logger.configure({
  formats: [`{{ date }}<=!=>{{ args | message }}`],
  pipes: {
    message(args: any[]): string {
      return args.join(' ');
    },
  },
});

Creating new logger instance

import { Logger } from '@evojs/logger';

const logger = new Logger({ name: 'request' });

export const requestLogger = responseTime((req: any, res: any, time: number) => {
  logger.info(
    chalk.green(req.method),
    chalk.yellow(res.statusCode),
    req.url,
    chalk.yellow(time.toFixed(0) + 'ms'),
    chalk.green(
      `${
        req.headers['x-forwarded-for'] || req.headers['x-real-ip'] || req.connection.remoteAddress
      }`,
    ),
    chalk.magenta(req.headers['user-agent']),
  );
});

Main features

1. Very flexible and easy to understand configuration
2. Metadata providing
3. Caller information
4. Console overriding
5. Typescript typings

License

Licensed under MIT license