Add Buffered interface for outputs that maintain an internal buffer

src/Logger.ts

@@ -1,5 +1,5 @@
 import { LogContext, LogLevel, LogMeta } from "./types/logger";
-import { Loggable, Storable } from "./interface/output";
+import { Buffered, Loggable, Storable } from "./interface/output";
 
 export class Logger {
   private outputs: Loggable[] = [];
@@ -17,8 +17,6 @@ export class Logger {
   }
 
   log(message: string, level: LogLevel, context: LogContext) {
-    // const label = getLabel(level);
-
     const meta: LogMeta = {
       level,
       time: new Date(),
@@ -55,4 +53,18 @@ export class Logger {
   fatal(message: string, context: LogContext = {}) {
     this.log(message, LogLevel.FATAL, context);
   }
+
+  async flush() {
+    const promises = [];
+
+    for (const output of this.outputs) {
+      // BUG: Typescript doesn't realize that outputs can be Storables or Buffered as well
+      // @ts-ignore
+      if (output.flush) {
+        promises.push((output as Buffered).flush());
+      }
+    }
+
+    await Promise.allSettled(promises);
+  }
 }

src/interface/output.ts

@@ -9,3 +9,7 @@ export abstract class Storable extends Loggable {
     entries: number
   ): Promise<{ message: string; meta: LogMeta; context: LogContext }[]>;
 }
+
+export abstract class Buffered extends Storable {
+  abstract flush(): Promise<void>;
+}

src/outputs/Tampermonkey.ts

@@ -1,4 +1,4 @@
-import { Storable } from "../interface/output";
+import { Buffered } from "../interface/output";
 import {
   StrictTampermonkeyOutputConfig,
   TampermonkeyBucketInfo,
@@ -7,7 +7,7 @@ import {
 import { gzip, randomString, ungzip } from "../lib/utilities";
 import { LogContext, LogData, LogMeta } from "../types/logger";
 
-export default class Tampermonkey implements Storable {
+export default class Tampermonkey implements Buffered {
   private buffer: LogData[];
   private bucketList: TampermonkeyBucketInfo[];
   private bufferCapacity: number;