Update README based on naming convention change.

Taking advantage of the new LogMessageFormatter return type, the
ConsoleLogAppender logs the formatted message as-is if it is a string,
but when processing structured data inserts a string summary consisting
of the message level, scope, and message summary or method. The full
object is still logged to the console as well for inspection.

README.md

@@ -54,7 +54,7 @@ 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
+the *LogMessage* interface. Notably, the *msg* field can be either a string
 or an object, allowing for the addition of arbitrary fields to be added to the
 log event.
 
@@ -65,9 +65,9 @@ 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`
+automatically persist log messages as structured data, flattening the `msg`
 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
+JSON object, promoting fields in the `msg` object to top-level fields in
 the output. For example:
 
 ```typescript
@@ -87,24 +87,24 @@ 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":"INFO","scope":"example","msg":"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.
+"msg". 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
+used as keys in the msg object (and will be ignored if they are). So, for
 example:
 
 ```typescript
-logger.debug({ level: 'WARN', message: 'Example of ignored fields', timestamp: 'today' });
+logger.debug({ level: 'WARN', msg: '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"}
+{"timestamp":"2021-09-01T00:00:00.000Z","level":"DEBUG","scope":"example","msg":"Example of ignored fields"}
 ```
 
 This flattening behavior is implemented in the `flattenMessage` function

eslint.config.mjs

@@ -25,6 +25,14 @@ const customTypescriptConfig = {
   rules: {
     'linebreak-style': ['error', 'unix'],
     quotes: ['error', 'single', { avoidEscape: true }],
+    semi: ['error', 'never'],
+    '@typescript-eslint/no-unused-vars': ['error', {
+      'args': 'all',
+      'argsIgnorePattern': '^_',
+      'caughtErrorsIgnorePattern': '^_',
+      'destructuredArrayIgnorePattern': '^_',
+      'varsIgnorePattern': '^_',
+    }],
   },
 }
 
@@ -51,4 +59,10 @@ export default [
   eslintJs.configs.recommended,
   ...recommendedTypeScriptConfigs,
   customTypescriptConfig,
+  {
+    rules: {
+      quotes: ['error', 'single', { avoidEscape: true }],
+      semi: ['error', 'never'],
+    },
+  },
 ]

package.json

@@ -1,6 +1,6 @@
 {
   "name": "@jdbernard/logging",
-  "version": "2.0.0",
+  "version": "2.1.0",
   "description": "Simple Javascript logging service.",
   "main": "dist/index.js",
   "types": "dist/index.d.ts",
@@ -8,7 +8,7 @@
     "/dist"
   ],
   "scripts": {
-    "build": "tsc",
+    "build": "bunx tsc",
     "prepare": "npm run build",
     "test": "echo \"Error: no test specified\" && exit 1"
   },

src/console-log-appender.ts

@@ -3,12 +3,23 @@ import {
   LogLevel,
   LogMessage,
   LogMessageFormatter,
-} from './log-message';
-import { LogAppender } from './log-appender';
+} from "./log-message";
+import { LogAppender } from "./log-appender";
 
+/**
+ * A log appender that writes log messages to the console. The behavior of the
+ * log appender can be configured with a threshold level and a message
+ * formatter.
+ *
+ * When the message formatter returns a string value, that value is logged to
+ * the console as-is. When the message formatter returns an object, a summary
+ * string is logged to the console, followed by the object itself. This allows
+ * logs to be easily read in the console, while still providing the structured
+ * data for inspection in the browser's developer tools.
+ */
 export class ConsoleLogAppender implements LogAppender {
   public threshold = LogLevel.ALL;
-  public formatter: LogMessageFormatter = flattenMessage
+  public formatter: LogMessageFormatter = flattenMessage;
 
   constructor(threshold?: LogLevel, formatter?: LogMessageFormatter) {
     if (threshold) {
@@ -27,17 +38,13 @@ export class ConsoleLogAppender implements LogAppender {
     let logMethod = console.log;
     switch (msg.level) {
       case LogLevel.ALL:
-        logMethod = console.log;
-        break;
       case LogLevel.TRACE:
+      case LogLevel.LOG:
         logMethod = console.log;
         break;
       case LogLevel.DEBUG:
         logMethod = console.debug;
         break;
-      case LogLevel.LOG:
-        logMethod = console.log;
-        break;
       case LogLevel.INFO:
         logMethod = console.info;
         break;
@@ -50,12 +57,25 @@ export class ConsoleLogAppender implements LogAppender {
         break;
     }
 
-    const strMsg = this.formatter(msg);
+    const fmtMsg = this.formatter(msg);
 
-    if (msg.error || msg.stacktrace) {
-      logMethod(strMsg, msg.error ?? msg.stacktrace);
+    if (typeof fmtMsg === "string") {
+      if (msg.error || msg.stacktrace) {
+        logMethod(fmtMsg, msg.error ?? msg.stacktrace);
+      } else {
+        logMethod(fmtMsg);
+      }
     } else {
-      logMethod(strMsg);
+      const { message, _error, _stacktrace, ...rest } = fmtMsg;
+      const summary = `${LogLevel[msg.level]} -- ${msg.scope}: ${
+        message ?? fmtMsg.method
+      }\n`;
+
+      if (msg.error || msg.stacktrace) {
+        logMethod(summary, msg.error ?? msg.stacktrace, rest);
+      } else {
+        logMethod(summary, rest);
+      }
     }
   }
 }

src/log-message.ts

@@ -1,4 +1,4 @@
-import { omit } from './util'
+import { omit } from "./util";
 
 export enum LogLevel {
   ALL = 0,
@@ -25,7 +25,7 @@ export function parseLogLevel(
 export interface LogMessage {
   scope: string;
   level: LogLevel;
-  message: string | Record<string, unknown>;
+  msg: string | Record<string, unknown>;
   stacktrace?: string;
   error?: Error;
   timestamp: Date;
@@ -53,32 +53,34 @@ export type FlattenedLogMessage = Record<string, unknown>;
  * {"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] };
+export function flattenMessage(logMsg: LogMessage): FlattenedLogMessage {
+  if (typeof logMsg.msg === "string") {
+    return { ...logMsg, level: LogLevel[logMsg.level] };
   } else {
-    const { message, ...rest } = msg;
+    const { msg, ...rest } = logMsg;
     return {
-      ...omit(message, [
-        'scope',
-        'level',
-        'stacktrace',
-        'error',
-        'timestamp',
+      ...omit(msg, [
+        "scope",
+        "level",
+        "stacktrace",
+        "error",
+        "timestamp",
       ]),
       ...rest,
-      level: LogLevel[msg.level],
+      level: LogLevel[logMsg.level],
     };
   }
 }
-export type LogMessageFormatter = (msg: LogMessage) => string | FlattenedLogMessage;
+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}: ${msg.message}`;
+  return `[${msg.scope}] - ${msg.level}: ${msg.msg}`;
 }
 
 export default LogMessage;

src/logger.ts

@@ -55,7 +55,7 @@ export class Logger {
 
   public doLog(
     level: LogLevel,
-    message: Error | MessageType,
+    msg: Error | MessageType,
     stacktrace?: string,
   ): void {
     if (level < this.getEffectiveThreshold()) {
@@ -65,57 +65,57 @@ export class Logger {
     const logMsg: LogMessage = {
       scope: this.name,
       level,
-      message: '',
+      msg: '',
       stacktrace: '',
       timestamp: new Date(),
     };
 
-    if (message === undefined || message === null) {
-      logMsg.message = message;
+    if (msg === undefined || msg === null) {
+      logMsg.msg = msg;
       logMsg.stacktrace = stacktrace ?? '';
-    } else if (message instanceof Error) {
-      const error = message as Error;
+    } else if (msg instanceof Error) {
+      const error = msg as Error;
       logMsg.error = error;
-      logMsg.message = `${error.name}: ${error.message}`;
+      logMsg.msg = `${error.name}: ${error.message}`;
       logMsg.stacktrace = stacktrace ?? error.stack ?? '';
-    } else if (isDeferredMsg(message)) {
-      logMsg.message = message();
+    } else if (isDeferredMsg(msg)) {
+      logMsg.msg = msg();
       logMsg.stacktrace = stacktrace == null ? '' : stacktrace;
     } else {
       // string | object
-      logMsg.message = message;
+      logMsg.msg = msg;
       logMsg.stacktrace = stacktrace == null ? '' : stacktrace;
     }
 
     this.sendToAppenders(logMsg);
   }
 
-  public trace(message: Error | MessageType, stacktrace?: string): void {
-    this.doLog(LogLevel.TRACE, message, stacktrace);
+  public trace(msg: Error | MessageType, stacktrace?: string): void {
+    this.doLog(LogLevel.TRACE, msg, stacktrace);
   }
 
-  public debug(message: Error | MessageType, stacktrace?: string): void {
-    this.doLog(LogLevel.DEBUG, message, stacktrace);
+  public debug(msg: Error | MessageType, stacktrace?: string): void {
+    this.doLog(LogLevel.DEBUG, msg, stacktrace);
   }
 
-  public log(message: MessageType, stacktrace?: string): void {
-    this.doLog(LogLevel.LOG, message, stacktrace);
+  public log(msg: MessageType, stacktrace?: string): void {
+    this.doLog(LogLevel.LOG, msg, stacktrace);
   }
 
-  public info(message: MessageType, stacktrace?: string): void {
-    this.doLog(LogLevel.INFO, message, stacktrace);
+  public info(msg: MessageType, stacktrace?: string): void {
+    this.doLog(LogLevel.INFO, msg, stacktrace);
   }
 
-  public warn(message: MessageType, stacktrace?: string): void {
-    this.doLog(LogLevel.WARN, message, stacktrace);
+  public warn(msg: MessageType, stacktrace?: string): void {
+    this.doLog(LogLevel.WARN, msg, stacktrace);
   }
 
-  public error(message: Error | MessageType, stacktrace?: string): void {
-    this.doLog(LogLevel.ERROR, message, stacktrace);
+  public error(msg: Error | MessageType, stacktrace?: string): void {
+    this.doLog(LogLevel.ERROR, msg, stacktrace);
   }
 
-  public fatal(message: Error | MessageType, stacktrace?: string): void {
-    this.doLog(LogLevel.FATAL, message, stacktrace);
+  public fatal(msg: Error | MessageType, stacktrace?: string): void {
+    this.doLog(LogLevel.FATAL, msg, stacktrace);
   }
 
   protected sendToAppenders(logMsg: LogMessage) {