devtools-nestjs

A development tool for NestJS that provides detailed profiling information about request execution — inspired by Symfony's WebProfilerBundle.

Features

• Request profiler — collects method, URL, status code, headers, query params, and body
• Performance timeline — tracks event timing, memory usage, and total duration
• Exception tracking — captures thrown exceptions with full stack traces
• Route info — displays matched route, controller, and parameters
• Log collector — aggregates application logs per request
• Database queries — tracks SQL queries, durations, and slow query detection
• Cache operations — monitors cache hits, misses, and operation timing
• Debug toolbar — Symfony-style toolbar injected into responses with real-time token refresh
• Storage — file-based (CSV index + JSON profiles) or in-memory storage
• TypeORM integration — automatic query logging for TypeORM

Installation

npm install devtools-nestjs

Quick Start

import { Module } from '@nestjs/common';
import { ProfilerModule } from 'devtools-nestjs';

@Module({
  imports: [
    ProfilerModule.forRoot({
      toolbar: true,
    }),
  ],
})
export class AppModule {}

Visit http://localhost:3000/_profiler to browse collected profiles. The debug toolbar appears automatically at the bottom of HTML responses.

Configuration

| Option | Type | Default | Description | |---|---|---|---| | storage | 'file' \| 'memory' | 'file' | Storage backend | | storageDir | string | './.profiler' | Directory for file storage | | enabled | boolean | true | Enable/disable profiling | | toolbar | boolean | true | Show debug toolbar | | toolbarPath | string | '/_profiler/toolbar' | Toolbar endpoint | | profilerPath | string | '/_profiler' | Profiler panel endpoint | | autoCollect | boolean | true | Auto-register profiler interceptor | | typeorm | boolean | false | Enable TypeORM query logging |

Custom Collectors

import { BaseCollector, CollectData, CollectorRegistration } from 'devtools-nestjs';

export class MyCollector extends BaseCollector {
  get name(): string { return 'my-collector'; }
  getPriority(): number { return 50; }

  collect(data: CollectData): void {
    this.data = { /* your data */ };
  }
}

// Register in module
ProfilerModule.forRoot({
  collectors: [
    { collector: MyCollector, priority: 50 },
  ] as CollectorRegistration[],
});

Collectors

| Collector | Name | Priority | Data Collected | |---|---|---|---| | RequestCollector | request | 100 | Method, URL, headers, params, body, IP | | TimeCollector | time | 90 | Event timeline, duration, memory | | ExceptionCollector | exception | 80 | Exception message, name, stack trace | | LogCollector | log | 60 | Log entries by level | | DatabaseCollector | database | 50 | Query count, duration, slow queries | | CacheCollector | cache | 40 | Operations, hits, misses, hit rate |

Storage

File storage stores profiles as JSON files organized by token hash and indexes them in a CSV file. Profiles expire after 48 hours.

Memory storage keeps profiles in a Map, suitable for development or low-traffic environments.

License

MIT