Edit File - File Manager

Edit File: create-logger.js

/**
 * create-logger.js: Logger factory for winston logger instances.
 *
 * (C) 2010 Charlie Robbins
 * MIT LICENCE
 */

'use strict';

/**
 * Create a new instance of a winston Logger. Creates a new
 * prototype for each instance.
 * @param {!Object} opts - Options for the created logger.
 * @returns {Logger} - A newly created logger instance.
 */
module.exports = function () {
  var opts = arguments.length > 0 && arguments[0] !== undefined ? arguments[0] : {};
  //
  // Default levels: npm
  //
  opts.levels = opts.levels || config.npm.levels;

/**
   * DerivedLogger to attach the logs level methods.
   * @type {DerivedLogger}
   * @extends {Logger}
   */
  var DerivedLogger = /*#__PURE__*/function (_Logger) {
    _inherits(DerivedLogger, _Logger);
    /**
     * Create a new class derived logger for which the levels can be attached to
     * the prototype of. This is a V8 optimization that is well know to increase
     * performance of prototype functions.
     * @param {!Object} options - Options for the created logger.
     */
    function DerivedLogger(options) {
      _classCallCheck(this, DerivedLogger);
      return _callSuper(this, DerivedLogger, [options]);
    }
    return _createClass(DerivedLogger);
  }(Logger);
  var logger = new DerivedLogger(opts);

//
  // Create the log level methods for the derived logger.
  //
  Object.keys(opts.levels).forEach(function (level) {
    debug('Define prototype method for "%s"', level);
    if (level === 'log') {
      // eslint-disable-next-line no-console
      console.warn('Level "log" not defined: conflicts with the method "log". Use a different level name.');
      return;
    }

//
    // Define prototype methods for each log level e.g.:
    // logger.log('info', msg) implies these methods are defined:
    // - logger.info(msg)
    // - logger.isInfoEnabled()
    //
    // Remark: to support logger.child this **MUST** be a function
    // so it'll always be called on the instance instead of a fixed
    // place in the prototype chain.
    //
    DerivedLogger.prototype[level] = function () {
      // Prefer any instance scope, but default to "root" logger
      var self = this || logger;

// Optimize the hot-path which is the single object.
      for (var _len = arguments.length, args = new Array(_len), _key = 0; _key < _len; _key++) {
        args[_key] = arguments[_key];
      }
      if (args.length === 1) {
        var msg = args[0];
        var info = msg && msg.message && msg || {
          message: msg
        };
        info.level = info[LEVEL] = level;
        self._addDefaultMeta(info);
        self.write(info);
        return this || logger;
      }

// When provided nothing assume the empty string
      if (args.length === 0) {
        self.log(level, '');
        return self;
      }

// Otherwise build argument list which could potentially conform to
      // either:
      // . v3 API: log(obj)
      // 2. v1/v2 API: log(level, msg, ... [string interpolate], [{metadata}], [callback])
      return self.log.apply(self, [level].concat(args));
    };
    DerivedLogger.prototype[isLevelEnabledFunctionName(level)] = function () {
      return (this || logger).isLevelEnabled(level);
    };
  });
  return logger;
};

Back to File Manager