[WIP] Implement Logging Mechanism for Web Scraping Activities

lib/Logger.js

@@ -0,0 +1,101 @@
+/**
+ * Custom Logger for Osmosis Web Scraping
+ * Provides flexible logging mechanisms with configurable levels
+ */
+class Logger {
+  /**
+   * Logging levels from most verbose to least
+   * @enum {number}
+   */
+  static LEVELS = {
+    DEBUG: 0,
+    INFO: 1,
+    WARN: 2,
+    ERROR: 3,
+    SILENT: 4
+  };
+
+  /**
+   * Create a new Logger instance
+   * @param {Object} options - Logger configuration
+   * @param {number} [options.level=0] - Logging level
+   * @param {boolean} [options.timestamp=true] - Include timestamp in logs
+   * @param {function} [options.writer=console.log] - Custom log writer
+   */
+  constructor(options = {}) {
+    this.level = options.level !== undefined ? options.level : Logger.LEVELS.DEBUG;
+    this.timestamp = options.timestamp !== false;
+    this.writer = options.writer || console.log;
+  }
+
+  /**
+   * Generate log message with optional timestamp
+   * @param {string} level - Log level name
+   * @param {string} message - Log message
+   * @param {Object} [context] - Additional logging context
+   * @returns {string} Formatted log message
+   * @private
+   */
+  _formatMessage(level, message, context = {}) {
+    const timestamp = this.timestamp ? `[${new Date().toISOString()}] ` : '';
+    const contextStr = Object.keys(context).length > 0 
+      ? ` ${JSON.stringify(context)}` 
+      : '';
+    return `[${level}] ${message}${contextStr}`;
+  }
+
+  /**
+   * Shared logging method
+   * @param {number} logLevel - Logging level
+   * @param {string} levelName - Log level name
+   * @param {string} message - Log message
+   * @param {Object} [context] - Additional context
+   * @private
+   */
+  _log(logLevel, levelName, message, context) {
+    if (this.level <= logLevel) {
+      this.writer(this._formatMessage(levelName, message, context));
+    }
+  }
+
+  /**
+   * Log a debug message
+   * @param {string} message - Debug message
+   * @param {Object} [context] - Additional context
+   */
+  debug(message, context) {
+    this._log(Logger.LEVELS.DEBUG, 'DEBUG', message, context);
+  }
+
+  /**
+   * Log an informational message
+   * @param {string} message - Info message
+   * @param {Object} [context] - Additional context
+   */
+  info(message, context) {
+    this._log(Logger.LEVELS.INFO, 'INFO', message, context);
+  }
+
+  /**
+   * Log a warning message
+   * @param {string} message - Warning message
+   * @param {Object} [context] - Additional context
+   */
+  warn(message, context) {
+    this._log(Logger.LEVELS.WARN, 'WARN', message, context);
+  }
+
+  /**
+   * Log an error message
+   * @param {string} message - Error message
+   * @param {Object} [context] - Additional context
+   */
+  error(message, context) {
+    this._log(Logger.LEVELS.ERROR, 'ERROR', message, context);
+  }
+}
+
+// Export as a singleton to ensure consistent logging across the library
+const loggerInstance = new Logger();
+module.exports = loggerInstance;
+module.exports.Logger = Logger;

package.json

@@ -25,10 +25,12 @@
   },
   "devDependencies": {
     "jscs": ">=3.0.2",
-    "nodeunit": "0.11.3"
+    "nodeunit": "0.11.3",
+    "jest": "^29.7.0"
   },
   "scripts": {
-    "test": "node ./node_modules/.bin/nodeunit test"
+    "test": "jest",
+    "test:logger": "jest test/logger.js"
   },
   "license": "MIT",
   "main": "index",
@@ -37,6 +39,9 @@
   },
   "readmeFilename": "Readme.md",
   "bugs": {
-    "url": "https://github.com/rchipka/node-osmosis/issues"
+    "url": "https://github.com/rchipka/node-osmosis/issues"},
+  "jest": {
+    "testEnvironment": "node",
+    "testMatch": ["**/test/**/*.js"]
   }
-}
+}

test/logger.js

@@ -0,0 +1,58 @@
+const { Logger } = require('../lib/Logger');
+
+describe('Logger', () => {
+  let capturedLogs = [];
+  const mockWriter = (message) => capturedLogs.push(message);
+
+  beforeEach(() => {
+    capturedLogs = [];
+  });
+
+  test('log messages at different levels', () => {
+    const logger = new Logger({ 
+      level: Logger.LEVELS.DEBUG, 
+      timestamp: false,
+      writer: mockWriter 
+    });
+
+    logger.debug('Debug message');
+    logger.info('Info message');
+    logger.warn('Warning message');
+
+    expect(capturedLogs.length).toBe(3);
+    expect(capturedLogs[0]).toBe('[DEBUG] Debug message');
+    expect(capturedLogs[1]).toBe('[INFO] Info message');
+    expect(capturedLogs[2]).toBe('[WARN] Warning message');
+  });
+
+  test('respect logging levels', () => {
+    const logger = new Logger({ 
+      level: Logger.LEVELS.WARN, 
+      timestamp: false,
+      writer: mockWriter 
+    });
+
+    logger.debug('Debug message');
+    logger.info('Info message');
+    logger.warn('Warning message');
+    logger.error('Error message');
+
+    expect(capturedLogs.length).toBe(2);
+    expect(capturedLogs[0]).toBe('[WARN] Warning message');
+    expect(capturedLogs[1]).toBe('[ERROR] Error message');
+  });
+
+  test('support logging context', () => {
+    const logger = new Logger({ 
+      level: Logger.LEVELS.DEBUG, 
+      timestamp: false,
+      writer: mockWriter 
+    });
+
+    logger.info('Scraping page', { url: 'https://example.com', pageNumber: 1 });
+
+    expect(capturedLogs[0]).toBe(
+      '[INFO] Scraping page {"url":"https://example.com","pageNumber":1}'
+    );
+  });
+});

test/setup.js

@@ -0,0 +1,4 @@
+// Enable using describe and it globally
+global.describe = describe;
+global.it = it;
+global.beforeEach = beforeEach;