feat(destination-buffer): add SmartlogDestinationBuffer in-memory circular buffer destination with query/filter/pagination and tests

ts_destination_buffer/classes.destinationbuffer.ts

@@ -0,0 +1,67 @@
+import type { ILogDestination, ILogPackage, TLogLevel } from '../dist_ts_interfaces/index.js';
+
+export interface IDestinationBufferOptions {
+  maxEntries?: number;
+}
+
+export interface IBufferQueryOptions {
+  level?: TLogLevel | TLogLevel[];
+  search?: string;
+  limit?: number;
+  offset?: number;
+  since?: number;
+}
+
+export class SmartlogDestinationBuffer implements ILogDestination {
+  private logPackages: ILogPackage[] = [];
+  private maxEntries: number;
+
+  constructor(options?: IDestinationBufferOptions) {
+    this.maxEntries = options?.maxEntries ?? 2000;
+  }
+
+  public async handleLog(logPackage: ILogPackage): Promise<void> {
+    this.logPackages.push(logPackage);
+    if (this.logPackages.length > this.maxEntries) {
+      this.logPackages.shift();
+    }
+  }
+
+  public getEntries(options?: IBufferQueryOptions): ILogPackage[] {
+    const limit = options?.limit ?? 100;
+    const offset = options?.offset ?? 0;
+
+    let results = this.logPackages;
+
+    // Filter by level
+    if (options?.level) {
+      const levels = Array.isArray(options.level) ? options.level : [options.level];
+      results = results.filter((pkg) => levels.includes(pkg.level));
+    }
+
+    // Filter by search (message content)
+    if (options?.search) {
+      const searchLower = options.search.toLowerCase();
+      results = results.filter((pkg) => pkg.message.toLowerCase().includes(searchLower));
+    }
+
+    // Filter by timestamp
+    if (options?.since) {
+      results = results.filter((pkg) => pkg.timestamp >= options.since);
+    }
+
+    // Return newest-first, with pagination
+    return results
+      .slice()
+      .reverse()
+      .slice(offset, offset + limit);
+  }
+
+  public getEntryCount(): number {
+    return this.logPackages.length;
+  }
+
+  public clear(): void {
+    this.logPackages = [];
+  }
+}