Nest Graph Inspector

Nest Graph Inspector is a NestJS module to generate a runtime dependency graph in Markdown + Mermaid or JSON format from the Nest application container.

The generated graph shows:

• loaded modules from the root module
• import relationships between modules
• providers and controllers in each module
• dependencies between providers/controllers
• internal dependencies, external module dependencies, and selected NestJS core dependencies

[!NOTE] Result of markdown can be seen on https://github.com/albasyir/nest-graph-inspector/blob/main/src/graph-output.md

Use Cases

important to see what's actual problem that can be solved with this, we think you have them too!

Impact Analysis

• narrowing regression test scope to the most relevant modules/providers
• reducing unnecessary testing for unrelated areas
• understanding the likely blast radius before making a change

Test Prioritization

• selecting critical providers/use cases for fast validation
• understanding dependency chains between providers/controllers
• prioritizing which flows should be checked first after a change

Architecture Visibility

• onboarding engineers faster
• spotting highly coupled modules/providers
• making refactors safer by visualizing relationships before changes

Installation

npm install nest-graph-inspector

Version Supports

Official support: NestJS 10-11.

[!NOTE] Earlier versions may still work, but are not officially supported. If you still want to install it with an unsupported NestJS version, you can force install it with:

npm install nest-graph-inspector --force

When you test it and work prefectly, raise on issue so i will update support coverage too

Usage

forRoot

Static config.

import { Module } from '@nestjs/common';
import { AppModule } from './app.module';
import { NestGraphInspector } from 'nest-graph-inspector';

@Module({
  imports: [
    NestGraphInspector.forRoot({
      rootModule: AppModule,
      output: {
        file: 'test.md',
      },
    }),
  ],
})
export class RootModule {}

forRootAsync

Factory-based config.

NestGraphInspector.forRootAsync({
  useFactory() {
    return {
      rootModule: AppModule,
      output: {
        file: 'test.md',
      },
    };
  },
}),

Config

rootModule

Graph entry point.

rootModule: AppModule

output.file

Output markdown file name.

output: {
  file: 'test.md'
}

Output

all output will contains

• module list
• imports module
• exports provider
• providers with dependencies
• controllers with dependencies

when markdown file as output, it will show depedencies graph

markdown use mermaid, open markdown in place that support mermaid, in VSC you can install plugin

Flow

1. start from the configured root module
2. inspect the Nest runtime container
3. collect module and provider metadata
4. resolve dependencies
5. generate output

Notes

• the graph is generated from the runtime Nest container, not from static source parsing
• selected NestJS core dependencies can be grouped under NestJS Core Module as Global Module