feat: add fatal log level support (#22)

.changeset/tall-suits-lie.md

@@ -0,0 +1,10 @@
+---
+"loglayer": minor
+---
+
+Add `fatal` log level support
+
+- Adds the `fatal()` method in `loglayer` to write to a `fatal` 
+log level.
+  * Any logging libraries that do not support `fatal` level will 
+  be written as an `error` level instead.

README.md

@@ -319,7 +319,7 @@ app.listen(port, () => {
 
 Generics (all are optional):
 
-- `LoggerInstanceType`: A definition that implements log `info` / `warn` / `error` / `trace` / `debug` methods.
+- `LoggerInstanceType`: A definition that implements log `info` / `warn` / `error` / `trace` / `debug` / `fatal` methods.
   * Used for returning the proper type in the `getLoggerInstance()` method.
 - `ErrorType`: A type that represents the `Error` type. Used with the serializer and error methods. Defaults to `any`.
 
@@ -563,9 +563,16 @@ const childLog = parentLog.child()
 - `LogLayer#error(...messages: MessageDataType[]): void`
 - `LogLayer#debug(...messages: MessageDataType[]): void`
 - `LogLayer#trace(...messages: MessageDataType[]): void`
+- `LogLayer#fatal(...messages: MessageDataType[]): void`
 
 `type MessageDataType = string | number | null | undefined`
 
+Some logging libraries do not support a `trace` or `fatal` level. `loglayer` will re-map
+to the following levels in that situation:
+
+  * `trace` -> `debug`
+  * `fatal` -> `error`
+
 *Your logging library may or may not support passing multiple parameters. See your logging library's 
 documentation for more details.*
 

livetests/utils.ts

@@ -1,50 +1,53 @@
-import { LogLayer } from '../src/LogLayer'
+import type { LogLayer } from "../src";
 
 export function testMethods(p: LogLayer) {
-  console.log('===== info() ====')
-  p.info('info', 'message', '3')
+  console.log("===== info() ====");
+  p.info("info", "message", "3");
 
-  console.log('===== warn() ====')
-  p.warn('warn message %s', 1)
+  console.log("===== warn() ====");
+  p.warn("warn message %s", 1);
 
-  console.log('===== error() ====')
-  p.error('error message')
+  console.log("===== error() ====");
+  p.error("error message");
 
-  console.log('===== debug() ====')
-  p.debug('debug message')
+  console.log("===== debug() ====");
+  p.debug("debug message");
 
-  console.log('===== trace() ====')
-  p.trace('trace message')
+  console.log("===== trace() ====");
+  p.trace("trace message");
 
-  console.log('===== withMetadata() ====')
+  console.log("===== fatal() ====");
+  p.fatal("fatal message");
+
+  console.log("===== withMetadata() ====");
   p.withMetadata({
-    test: 'metadata',
-    test2: 'metadata2',
-  }).trace('trace message')
+    test: "metadata",
+    test2: "metadata2",
+  }).trace("trace message");
 
-  console.log('===== withError() ====')
-  p.withError(new Error('error object')).trace('trace message')
+  console.log("===== withError() ====");
+  p.withError(new Error("error object")).trace("trace message");
 
-  console.log('===== withError() + withMetadata() ====')
+  console.log("===== withError() + withMetadata() ====");
   p.withMetadata({
-    test: 'metadata',
-    test2: 'metadata2',
+    test: "metadata",
+    test2: "metadata2",
   })
-    .withError(new Error('error object'))
-    .error('error message')
+    .withError(new Error("error object"))
+    .error("error message");
 
-  console.log('===== onlyError() ====')
-  p.errorOnly(new Error('error message'))
+  console.log("===== onlyError() ====");
+  p.errorOnly(new Error("error message"));
 
-  console.log('===== onlyMetadata() ====')
+  console.log("===== onlyMetadata() ====");
   p.metadataOnly({
-    only: 'metadata',
-  })
+    only: "metadata",
+  });
 
-  console.log('===== withContext() ====')
+  console.log("===== withContext() ====");
   p.withContext({
-    test: 'data',
-  })
+    test: "data",
+  });
 
-  p.info('context data')
+  p.info("context data");
 }

package.json

@@ -33,7 +33,7 @@
     "livetest:pino": "ts-node-dev livetests/pino.ts",
     "livetest:roarr": "ROARR_LOG=true ts-node-dev livetests/roarr.ts",
     "livetest:winston": "ts-node-dev livetests/winston.ts",
-    "livetest:log4js": "ts-node-dev livetests/log4js-node.ts",
+    "livetest:log4js-node": "ts-node-dev livetests/log4js-node.ts",
     "prepare": "husky install",
     "release": "changeset publish",
     "test": "vitest run",

src/LogBuilder.ts

@@ -98,6 +98,17 @@ export class LogBuilder<ExternalLogger extends LoggerLibrary = LoggerLibrary, Er
     this.formatLog(LogLevel.trace, messages);
   }
 
+  /**
+   * Sends a log message to the logging library under the fatal log level
+   *
+   * The logging library may or may not support multiple message parameters and only
+   * the first parameter would be used.
+   */
+  fatal(...messages: MessageDataType[]) {
+    this.structuredLogger._formatMessage(messages);
+    this.formatLog(LogLevel.fatal, messages);
+  }
+
   /**
    * All logging inputs are dropped and stops sending logs to the logging library.
    */