.gitignore

@@ -1,5 +1,3 @@
 node_modules/
 dist/
 *.sw?
-.lvimrc
-jdbernard-logging-*.tgz

README.md

@@ -1,166 +0,0 @@
-# Overview
-
-`@jdbernard/logging` implements a simple but powerful logging system for
-JavaScript applications based on the idea of heirarchical loggers. It heavily
-inspired by the usage patterns of [log4j][], [logback][], and similar tools in other
-ecosystems.
-
-## Getting Started
-
-Install the package from npm:
-```bash
-npm install @jdbernard/logging
-```
-
-Then, in your application, you can use the logging system like so:
-
-```typescript
-import { logService, ConsoleAppender, LogLevel } from '@jdbernard/logging';
-
-logService.ROOT_LOGGER.appenders.push(new ConsoleAppender(LogLevel.INFO));
-const logger = logService.getLogger('example');
-
-logger.info('Starting application');
-```
-
-## Loggers and Appenders
-
-The logging system is composed of two main components: loggers and appenders.
-Loggers are used to create log events, which are then passed to the appenders
-associated with the logger and it's parent. An appender is a function that
-takes a log event and writes it to some destination, such as the console, a
-file, or a network socket. Appenders also have a logging level threshold, which
-determines which log events are acted upon by the appender.
-
-Loggers are hierarchical, with the hierarchy defined by the logger name. When a
-log message is generated on a *Logger*, it is sent to any appenders associated
-with that logger, and then triggered on the parent logger, being sent to any of
-the parent logger's appenders, and so on up the hierarchy. Similarly, when a
-logging event is generated, it is filtered by the effective logging level of
-the logger. If there is no threshold set on the logger, the effective logging
-level is inherited from the parent logger. This pattern is explained in detail
-in the [logback documentation][effective logging level] and applies in the same
-manner to this library.
-
-Together, the cascading effective logging threshold and the upward propogation
-of log events to parent appenders allows for simple yet fine-grained control
-over the logging output of an application.
-
-## Layouts
-
-One difference from other logging libraries is the absense of layouts. Layouts
-are used in many logging libraries to format the log message before it is
-written to the appender. This requires the assumption of all logs being written
-to a text-based destination, which is not always the case for us.
-
-In this library, all logs are internally stored as structured data, defined by
-the *LogMessage* interface. Notably, the *message* field can be either a string
-or an object, allowing for the addition of arbitrary fields to be added to the
-log event.
-
-The concept of Layouts still has a place, but it has been moved to be an
-implementation detail of the appenders. *ConsoleAppender* accepts a
-*LogMessageFormatter* function allowing for formatting of the resulting
-messages written to the console. the *ApiAppender* would be an example of an
-appender for which layout would be irrelevant.
-
-Finally, notice that all of the appenders provided by this library
-automatically persist log messages as structured data, flattening the `message`
-field if it is an object. *ConsoleAppender* will write the log message as a
-JSON object, promoting fields in the `message` object to top-level fields in
-the output. For example:
-
-```typescript
-import { logService, ConsoleAppender } from '@jdbernard/logging';
-
-logService.ROOT_LOGGER.appenders.push(new ConsoleAppender('TRACE'));
-const logger = logService.getLogger('example');
-
-function someBusinessLogic() {
-  logger.debug({ method: 'someBusinessLogic', msg: 'Doing some business logic', foo: 'bar' });
-}
-
-logger.info('Starting application');
-someBusinessLogic();
-```
-
-results in the following two events logged as output to the console:
-
-```json
-{"timestamp":"2021-09-01T00:00:00.000Z","level":"INFO","scope":"example","message":"Starting application"}
-{"timestamp":"2021-09-01T00:00:00.000Z","level":"DEBUG","scope":"example","msg":"Doing some business logic","method":"someBusinessLogic","foo":"bar"}
-```
-
-Note that the field name in the structured data for string messages is
-"message". In the case of an object message, the fields are used as provided.
-Fields defined on the *LogMessage* interface are reserved and should not be
-used as keys in the message object (and will be ignored if they are). So, for
-example:
-
-```typescript
-logger.debug({ level: 'WARN', message: 'Example of ignored fields', timestamp: 'today' });
-
-results in the following event logged as output to the console (note the
-ignored `level` and `timestamp` fields from the object):
-
-```json
-{"timestamp":"2021-09-01T00:00:00.000Z","level":"DEBUG","scope":"example","message":"Example of ignored fields"}
-```
-
-This flattening behavior is implemented in the `flattenMessage` function
-exported from the `@jdbernard/logging/log-message.ts` module and is available
-for use in custom appender implemetations.
-
-As a final note, the *ConsoleAppender* has some special behavior for the ERROR
-level and *stacktrace* field when running in a web browser to take advantage of
-the console's built-in. See the documentation for the *ConsoleAppender* for
-more information.
-
-## Worked Example
-
-To illustrate the usage of the logging system and the purpose of the
-fine-grained control described above, consider the following TypeScript
-example:
-
-```typescript
-// main.ts -- Entry point of the application
-// A console appender is attached to the root logger to log all events at or
-// above the INFO level.
-logService.ROOT_LOGGER.appenders.push(new ConsoleAppender(LogLevel.INFO));
-
-// An API appender is attached to the root logger to forward all ERROR events
-// to a server-side error log collector.
-logServive.ROOT_LOGGER.appenders.push(new ApiAppender(
-  'https://api.example.com/error-logs',
-  appStore.user.sessionToken,
-  LogLevel.ERROR));
-
-const appLog = logService.getLogger('app');
-appLog.info('Starting application');
-
-// api.ts -- API implementaiton
-const apiLog = logService.getLogger('app/api');
-
-// http-client.ts -- HTTP client implementation
-const httpLog = logService.getLogger('app/api/http-client');
-```
-
-Because different parts of the application use namespaced loggers, we can
-dynamically adjust the logging level of different parts of the application
-without changing the code. For example, to increase the logging level of the
-HTTP client to DEBUG, we can add the following line to the `main.ts` file:
-
-```typescript
-logService.getLogger('app/api/http-client').setLevel(LogLevel.DEBUG);
-```
-
-Additionally, if, for some reason, we only wanted to forward the ERROR events
-from the API namespace to the server-side error log collector, we could attach
-the *ApiAppender* to the `app/api` logger instead of the root logger. This
-would allow us to log all events from both the API and HTTP client loggers to
-the API log collector, but ignore the rest of the application regardless of the
-logging level.
-
-[log4j]: https://logging.apache.org/log4j/2.x/
-[logback]: https://logback.qos.ch/
-[effective logging level]: https://logback.qos.ch/manual/architecture.html#effectiveLevel

eslint.config.mjs

@@ -1,54 +0,0 @@
-import importPlugin from 'eslint-plugin-import'
-import tsParser from '@typescript-eslint/parser'
-import eslintJs from '@eslint/js'
-import eslintTs from 'typescript-eslint'
-
-const tsFiles = ['src/**/*.ts']
-
-const customTypescriptConfig = {
-  files: tsFiles,
-  plugins: {
-    import: importPlugin,
-    'import/parsers': tsParser,
-  },
-  languageOptions: {
-    parser: tsParser,
-    parserOptions: {
-      project: './tsconfig.json',
-    },
-  },
-  settings: {
-    'import/parsers': {
-      '@typescript-eslint/parser': ['.ts'],
-    },
-  },
-  rules: {
-    'linebreak-style': ['error', 'unix'],
-    quotes: ['error', 'single', { avoidEscape: true }],
-  },
-}
-
-const recommendedTypeScriptConfigs = [
-  ...eslintTs.configs.recommended.map((config) => ({
-    ...config,
-    files: tsFiles,
-  })),
-  ...eslintTs.configs.stylistic.map((config) => ({
-    ...config,
-    files: tsFiles,
-  })),
-]
-
-export default [
-  {
-    ignores: [
-      'docs/*',
-      'build/*',
-      'lib/*',
-      'dist/*',
-    ],
-  }, // global ignores
-  eslintJs.configs.recommended,
-  ...recommendedTypeScriptConfigs,
-  customTypescriptConfig,
-]

package-lock.json

@@ -0,0 +1,29 @@
+{
+  "name": "@jdbernard/logging",
+  "version": "1.1.5",
+  "lockfileVersion": 3,
+  "requires": true,
+  "packages": {
+    "": {
+      "name": "@jdbernard/logging",
+      "version": "1.1.4",
+      "license": "GPL-3.0",
+      "devDependencies": {
+        "typescript": "^5.0.4"
+      }
+    },
+    "node_modules/typescript": {
+      "version": "5.0.4",
+      "resolved": "https://registry.npmjs.org/typescript/-/typescript-5.0.4.tgz",
+      "integrity": "sha512-cW9T5W9xY37cc+jfEnaUvX91foxtHkza3Nw3wkoF4sSlKn0MONdkdEndig/qPBWXNkmplh3NzayQzCiHM4/hqw==",
+      "dev": true,
+      "bin": {
+        "tsc": "bin/tsc",
+        "tsserver": "bin/tsserver"
+      },
+      "engines": {
+        "node": ">=12.20"
+      }
+    }
+  }
+}

package.json

@@ -1,6 +1,6 @@
 {
   "name": "@jdbernard/logging",
-  "version": "2.0.0",
+  "version": "1.1.5",
   "description": "Simple Javascript logging service.",
   "main": "dist/index.js",
   "types": "dist/index.d.ts",
@@ -23,9 +23,6 @@
   "author": "Jonathan Bernard",
   "license": "GPL-3.0",
   "devDependencies": {
-    "@typescript-eslint/parser": "^8.19.0",
+    "typescript": "^5.0.4"
-    "eslint-plugin-import": "^2.31.0",
-    "typescript": "^5.0.4",
-    "typescript-eslint": "^8.19.0"
   }
 }

src/api-log-appender.ts

@@ -1,13 +1,20 @@
-import { LogMessage, LogLevel, flattenMessage, FlattenedLogMessage } from './log-message';
+import { LogMessage, LogLevel } from './log-message';
-import { LogAppender } from './log-appender';
+import LogAppender from './log-appender';
 
+interface ApiMessage {
+  level: string;
+  message: string;
+  scope: string;
+  stacktrace: string;
+  timestamp: string;
+}
 export class ApiLogAppender implements LogAppender {
   public batchSize = 10;
   public minimumTimePassedInSec = 60;
   public maximumTimePassedInSec = 120;
   public threshold = LogLevel.ALL;
 
-  private msgBuffer: FlattenedLogMessage[] = [];
+  private msgBuffer: ApiMessage[] = [];
   private lastSent = 0;
 
   constructor(
@@ -26,7 +33,16 @@ export class ApiLogAppender implements LogAppender {
       return;
     }
 
-    this.msgBuffer.push(flattenMessage(msg));
+    this.msgBuffer.push({
+      level: LogLevel[msg.level],
+      message:
+        typeof msg.message === 'string'
+          ? msg.message
+          : JSON.stringify(msg.message),
+      scope: msg.scope,
+      stacktrace: msg.stacktrace,
+      timestamp: msg.timestamp.toISOString()
+    });
   }
 
   private doPost() {

src/console-log-appender.ts

@@ -1,22 +1,14 @@
-import {
+/*tslint:disable:no-console*/
-  flattenMessage,
+import { LogMessage, LogLevel } from './log-message';
-  LogLevel,
+import LogAppender from './log-appender';
-  LogMessage,
-  LogMessageFormatter,
-} from './log-message';
-import { LogAppender } from './log-appender';
 
 export class ConsoleLogAppender implements LogAppender {
   public threshold = LogLevel.ALL;
-  public formatter: LogMessageFormatter = flattenMessage
 
-  constructor(threshold?: LogLevel, formatter?: LogMessageFormatter) {
+  constructor(threshold?: LogLevel) {
     if (threshold) {
       this.threshold = threshold;
     }
-    if (formatter) {
-      this.formatter = formatter;
-    }
   }
 
   public appendMessage(msg: LogMessage): void {
@@ -50,12 +42,12 @@ export class ConsoleLogAppender implements LogAppender {
         break;
     }
 
-    const strMsg = this.formatter(msg);
+    if (msg.error) {
-
+      logMethod(`[${msg.scope}]:`, msg.message, msg.error);
-    if (msg.error || msg.stacktrace) {
+    } else if (msg.stacktrace) {
-      logMethod(strMsg, msg.error ?? msg.stacktrace);
+      logMethod(`[${msg.scope}]:`, msg.message, msg.stacktrace);
     } else {
-      logMethod(strMsg);
+      logMethod(`[${msg.scope}]:`, msg.message);
     }
   }
 }

src/log-appender.ts

@@ -1,8 +1,5 @@
 import { LogLevel, LogMessage } from './log-message';
-
+export default interface LogAppender {
-export interface LogAppender {
   threshold: LogLevel;
   appendMessage(message: LogMessage): void;
 }
-
-export default LogAppender;

src/log-message.ts

@@ -1,5 +1,3 @@
-import { omit } from './util'
-
 export enum LogLevel {
   ALL = 0,
   TRACE,
@@ -8,15 +6,12 @@ export enum LogLevel {
   INFO,
   WARN,
   ERROR,
-  FATAL,
+  FATAL
 }
 
-export function parseLogLevel(
+export function parseLogLevel(str: string, defaultLevel = LogLevel.INFO): LogLevel {
-  str: string,
+  if (Object.prototype.hasOwnProperty.call(LogLevel, str)) {
-  defaultLevel = LogLevel.INFO,
+    return LogLevel[<any>str] as unknown as LogLevel;
-): LogLevel {
-  if (str in LogLevel) {
-    return LogLevel[str as keyof typeof LogLevel] as LogLevel;
   } else {
     return defaultLevel;
   }
@@ -25,60 +20,10 @@ export function parseLogLevel(
 export interface LogMessage {
   scope: string;
   level: LogLevel;
-  message: string | Record<string, unknown>;
+  message: string | object;
-  stacktrace?: string;
+  stacktrace: string;
   error?: Error;
   timestamp: Date;
 }
 
-export type FlattenedLogMessage = Record<string, unknown>;
-
-/**
- * Flatten a log message to a plain object. The *message* field can be either a
- * string or an object. In the case of an object message, the LogMessage should
- * be flattened before being emitted by an appender, promoting the object's
- * fields to the top level of the message. Fields defined on the *LogMessage*
- * interface are reserved and should not be used as keys in the message object
- * (and will be ignored if they are).
- *
- * So, for example:
- *
- * ```typescript
- * const logger = logService.getLogger('example');
- * logger.info({ foo: 'bar', baz: 'qux', timestamp: 'today', level: LogLevel.WARN });
- * ```
- *
- * Should result after flattening in a structured log message like:
- * ```json
- * {"scope":"example","level":"INFO","foo":"bar","baz":"qux","timestamp":"2020-01-01T00:00:00.000Z"}
- * ```
- */
-export function flattenMessage(msg: LogMessage): FlattenedLogMessage {
-  if (typeof msg.message === 'string') {
-    return { ...msg, level: LogLevel[msg.level] };
-  } else {
-    const { message, ...rest } = msg;
-    return {
-      ...omit(message, [
-        'scope',
-        'level',
-        'stacktrace',
-        'error',
-        'timestamp',
-      ]),
-      ...rest,
-      level: LogLevel[msg.level],
-    };
-  }
-}
-export type LogMessageFormatter = (msg: LogMessage) => string | FlattenedLogMessage;
-
-export function structuredLogMessageFormatter(msg: LogMessage): string {
-  return JSON.stringify(flattenMessage(msg));
-}
-
-export function simpleTextLogMessageFormatter(msg: LogMessage): string {
-  return `[${msg.scope}] - ${msg.level}: ${msg.message}`;
-}
-
 export default LogMessage;

src/log-service.ts

@@ -1,16 +1,10 @@
 import { LogLevel } from './log-message';
-import { Logger } from './logger';
+import Logger from './logger';
 
 const ROOT_LOGGER_NAME = 'ROOT';
 
-/**
- * Service for managing loggers. A LogService instance defines
- * the service context for a set of loggers. Typically there is only one
- * LogService instance per application, the one exported as default from this
- * module.
- */
 export class LogService {
-  private loggers: Record<string, Logger>;
+  private loggers: { [key: string]: Logger };
 
   public get ROOT_LOGGER() {
     return this.loggers[ROOT_LOGGER_NAME];
@@ -21,38 +15,10 @@ export class LogService {
     this.loggers[ROOT_LOGGER_NAME] = new Logger(
       ROOT_LOGGER_NAME,
       undefined,
-      LogLevel.ALL,
+      LogLevel.ALL
     );
   }
 
-  /**
-   * Get a logger by name. If the logger does not exist, it will be created.
-   * Loggers are hierarchical, with the heirarchy defined by the logger name.
-   * When creating a new logger, the parent logger is determined by the longest
-   * existing logger name that is a prefix of the new logger name. For example,
-   * if a logger with the name "foo" already exists, any subsequent loggers
-   * with the names "foo.bar", "foo/bar", "foolish.choice", etc. will be
-   * created as children of the "foo" logger.
-   *
-   * As another example, given the following invocations:
-   *
-   * ```typescript
-   * logService.getLogger('foo');
-   * logService.getLogger('foo.bar');
-   * logService.getLogger('foo.bar.baz');
-   * logService.getLogger('foo.qux');
-   * ```
-   *
-   * will result in the following logging hierarchy:
-   *
-   *     foo
-   *     ├─foo.bar
-   *     │ └─foo.bar.baz
-   *     └─foo.qux
-   *
-   * See the Logger class for details on how loggers are used and the
-   * implications of the logger hierarchy.
-   */
   public getLogger(name: string, threshold?: LogLevel): Logger {
     if (this.loggers[name]) {
       return this.loggers[name];
@@ -64,7 +30,7 @@ export class LogService {
       .filter((n: string) => name.startsWith(n))
       .reduce(
         (acc: string, cur: string) => (acc.length > cur.length ? acc : cur),
-        '',
+        ''
       );
 
     if (parentLoggerName) {

src/logger.ts

@@ -1,52 +1,16 @@
-import { LogLevel, LogMessage } from './log-message';
+import { LogMessage, LogLevel } from './log-message';
-import { LogAppender } from './log-appender';
+import LogAppender from './log-appender';
 
-export type DeferredMsg = () => string | Record<string, unknown>;
+export type DeferredMsg = () => string | object;
-export type MessageType = string | DeferredMsg | Record<string, unknown>;
+export type MessageType = string | DeferredMsg | object;
 
-export function isDeferredMsg(msg: MessageType): msg is DeferredMsg {
-  return typeof msg === 'function';
-}
-
-/**
- * Logger class for logging messages.
- *
- * Loggers are used to log messages at different levels. The levels are, in
- * order of increasing severity: TRACE, DEBUG, LOG, INFO, WARN, ERROR, FATAL.
- * Log messages can be logged at a specific level by calling the corresponding
- * method on the logger instance. For example, to log a message at the INFO
- * level, call the *info* method on the logger.
- *
- * Loggers have a threshold level, which is the minimum level of log message
- * that will be logged by the logger. Log messages with a level below the
- * threshold will be ignored. The threshold level can be set when creating a
- * logger, or by calling the *setThreshold* method on an existing logger. If a
- * threshold is not set, the logger will use the threshold of its parent
- * logger.
- *
- * Loggers are hierarchical, with the hierarchy defined by the logger name.
- * The heirarchy is tracked by the children: child loggers have a link to their
- * parents, while parent loggers do not have a list of their children.
- *
- * When a log message is logged by a logger, it is sent to all of the appenders
- * attached to the logger and to the parent logger. Appenders can be attached
- * to any Logger instance, but, because of this upwards propogation, appenders
- * are usually attached to the root logger, which is an ancestor of all loggers
- * created by the same LogService instance.
- *
- * Loggers are typically created and managed by a LogService instance.  The
- * *LogService#getLogger* method is used to get a logger by name, creating it
- * if necessary. When creating a new logger, the parent logger is determined by
- * the longest existing logger name that is a prefix of the new logger name.
- * For more details, see *LogService#getLogger*.
- */
 export class Logger {
   public appenders: LogAppender[] = [];
 
   public constructor(
     public readonly name: string,
     private parentLogger?: Logger,
-    public threshold?: LogLevel,
+    public threshold?: LogLevel
   ) {}
 
   public createChildLogger(name: string, threshold?: LogLevel): Logger {
@@ -56,7 +20,7 @@ export class Logger {
   public doLog(
     level: LogLevel,
     message: Error | MessageType,
-    stacktrace?: string,
+    stacktrace?: string
   ): void {
     if (level < this.getEffectiveThreshold()) {
       return;
@@ -67,20 +31,20 @@ export class Logger {
       level,
       message: '',
       stacktrace: '',
-      timestamp: new Date(),
+      timestamp: new Date()
     };
 
     if (message === undefined || message === null) {
       logMsg.message = message;
-      logMsg.stacktrace = stacktrace ?? '';
+      logMsg.stacktrace = stacktrace == null ? '' : stacktrace;
+    } else if ((message as DeferredMsg).call !== undefined) {
+      logMsg.message = (message as DeferredMsg)();
+      logMsg.stacktrace = stacktrace == null ? '' : stacktrace;
     } else if (message instanceof Error) {
       const error = message as Error;
       logMsg.error = error;
       logMsg.message = `${error.name}: ${error.message}`;
-      logMsg.stacktrace = stacktrace ?? error.stack ?? '';
+      logMsg.stacktrace = error.stack == null ? '' : error.stack;
-    } else if (isDeferredMsg(message)) {
-      logMsg.message = message();
-      logMsg.stacktrace = stacktrace == null ? '' : stacktrace;
     } else {
       // string | object
       logMsg.message = message;
@@ -119,7 +83,7 @@ export class Logger {
   }
 
   protected sendToAppenders(logMsg: LogMessage) {
-    this.appenders.forEach((app) => {
+    this.appenders.forEach(app => {
       app.appendMessage(logMsg);
     });
 

src/util.ts

@@ -1,12 +0,0 @@
-export function omit(
-  obj: Record<string, unknown>,
-  keys: string[],
-): Record<string, unknown> {
-  const result: Record<string, unknown> = {};
-  for (const key in obj) {
-    if (!keys.includes(key)) {
-      result[key] = obj[key];
-    }
-  }
-  return result;
-}

tsconfig.json

@@ -1,7 +1,7 @@
 {
   "compilerOptions": {
     "module": "commonjs",
-    "target": "es2016",
+    "target": "es6",
     "declaration": true,
     "outDir": "./dist",
     "strict": true,