index.js

/* eslint-disable security/detect-object-injection */
const fs = require('fs');
const path = require('path');

class Logger {
  // Requires Node v12+
  // static COLORS = {
  //   ERROR: '\x1b[31m%s', // Red
  //   WARN: '\x1b[33m%s', // Yellow
  //   SUCCESS: '\x1b[32m%s', // Green
  //   INFO: '\x1b[37m%s', // White
  //   DEBUG: '\x1b[36m%s', // Cyan
  //   CLEAR: '\x1b[0m' // Clear
  // };

  constructor(config = { levels: ['ERROR', 'WARN', 'SUCCESS', 'INFO', 'DEBUG'] }) {

    this.COLORS = {
      ERROR: '\x1b[31m%s', // Red
      WARN: '\x1b[33m%s', // Yellow
      SUCCESS: '\x1b[32m%s', // Green
      INFO: '\x1b[37m%s', // White
      DEBUG: '\x1b[36m%s', // Cyan
      CLEAR: '\x1b[0m' // Clear
    };

    this.label = config.label || '';

    this.timestampStr = () => {
      switch (config.timestamp) {
        case 'iso':
          return (new Date()).toISOString();
        case 'locale':
          return (new Date()).toLocaleString();
        default:
          return Logger.toCLFDateTimeString();
      }
    };

    if (config.console === 'file' || config.console === 'both') {
      try {
        // eslint-disable-next-line no-bitwise
        fs.accessSync(path.dirname(config.file), fs.constants.F_OK | fs.constants.W_OK);
        const mode = config.append ? 'a' : 'w';
        // eslint-disable-next-line security/detect-non-literal-fs-filename
        const logFile = fs.createWriteStream(config.file, { flags: mode });
        if (config.console === 'both') { // file & console
          this.log = (level, ...msg) => {
            if (config.levels.includes(level)) {
              logFile.write(`${[level, ...msg].join(' ')}\n`);
              // eslint-disable-next-line no-console
              console.log(this.COLORS[level], ...msg, this.COLORS.CLEAR);
            }
          };
        }
        else { // file only
          this.log = (level, ...msg) => {
            if (config.levels.includes(level)) {
              logFile.write(`${[level, ...msg].join(' ')}\n`);
            }
          };
        }
      } catch (err) {
        // eslint-disable-next-line no-console
        console.log('Log directory is not writable: ', err);
        throw new Error('Log directory is not writable');
      }
    } else { // console only
      this.log = (level, ...msg) => {
        if (config.levels.includes(level)) {
          // eslint-disable-next-line no-console
          console.log(this.COLORS[level], ...msg, this.COLORS.CLEAR);
        }
      };
    }
  }

  error(...msg) {
    this.log('ERROR', this.timestampStr(), this.label, ...msg);
  }

  warn(...msg) {
    this.log('WARN', this.timestampStr(), this.label, ...msg);
  }

  success(...msg) {
    this.log('SUCCESS', this.timestampStr(), this.label, ...msg);
  }

  info(...msg) {
    this.log('INFO', this.timestampStr(), this.label, ...msg);
  }

  debug(...msg) {
    this.log('DEBUG', this.timestampStr(), this.label, ...msg);
  }

  static toCLFDateTimeString(dateTime = new Date()) {
    const pad2 = (n) => {
      const str = n.toString();
      return (str.length === 1 ? '0' : '') + str;
    };
    const MONTH3 = [
      'Jan', 'Feb', 'Mar', 'Apr', 'May', 'Jun',
      'Jul', 'Aug', 'Sep', 'Oct', 'Nov', 'Dec',
    ];
    const date = dateTime.getUTCDate();
    const hour = dateTime.getUTCHours();
    const mins = dateTime.getUTCMinutes();
    const secs = dateTime.getUTCSeconds();
    const year = dateTime.getUTCFullYear();
    const month = MONTH3[dateTime.getUTCMonth()];

    return (`${pad2(date)}/${month}/${year}:${pad2(hour)}:${pad2(mins)}:${pad2(secs)} +0000`);
  }
}

module.exports=Logger;