@bvhoach2393/nest-sum

A NestJS library for safe number summation with MAX_VALUE validation.

Features

• Validates input numbers against a configurable MAX_VALUE
• Integrates with NestJS ConfigService
• Provides clear error messages for validation failures
• Full TypeScript support

Installation

npm install @bvhoach2393/nest-sum

Usage

1. Import the module

import { Module } from '@nestjs/common';
import { ConfigModule } from '@nestjs/config';
import { NestSumModule } from '@bvhoach2393/nest-sum';

@Module({
  imports: [
    ConfigModule.forRoot({
      isGlobal: true,
    }),
    NestSumModule,
  ],
})
export class AppModule {}

2. Use the service

import { Injectable } from '@nestjs/common';
import { NestSumService } from '@bvhoach2393/nest-sum';

@Injectable()
export class MyService {
  constructor(private readonly nestSumService: NestSumService) {}

  calculateSum(a: number, b: number): number {
    return this.nestSumService.sum(a, b);
  }
}

3. Environment configuration

Set the MAX_VALUE in your environment variables:

MAX_VALUE=1000

API

sum(a: number, b: number): number

Calculates the sum of two numbers with validation.

Parameters:

• a: First number
• b: Second number

Returns:

• The sum of a and b

Throws:

• Error if MAX_VALUE is not configured
• Error if either a or b exceeds MAX_VALUE

Example

// With MAX_VALUE=100
nestSumService.sum(30, 40); // Returns 70
nestSumService.sum(150, 20); // Throws error: exceeds MAX_VALUE

Testing

Running Unit Tests

To run the unit tests for this library:

# Run tests for the nest-sum library
npm test -- libs/nest-sum

# Run tests with coverage
npm run test:cov -- libs/nest-sum

# Run tests in watch mode
npm run test:watch -- libs/nest-sum

Test Coverage

The library includes comprehensive unit tests covering:

• ✅ Service initialization
• ✅ Valid sum calculation within MAX_VALUE
• ✅ Error handling when MAX_VALUE is not configured
• ✅ Validation when parameters exceed MAX_VALUE
• ✅ Console logging for error cases

Development

Local Development

1. Clone the repository
2. Install dependencies: npm install
3. Set up environment: cp .env.example .env
4. Build the library: npm run build:lib
5. Run tests: npm test -- libs/nest-sum

Building

# Build the library
npm run build:lib

# Build all projects
npm run build

Publishing to NPM Registry

Prerequisites

1. Create an NPM account at npmjs.com
2. Login to NPM: npm login
3. Verify your account: npm whoami

Publishing Steps

# 1. Navigate to the library directory
cd libs/nest-sum

# 2. Update version in package.json if needed
npm version patch  # or minor/major

# 3. Build the library
cd ../..
npm run build:lib

# 4. Navigate back to library directory
cd libs/nest-sum

# 5. Publish to NPM
npm publish --access public

# For scoped packages, use:
npm publish --access public

Version Management

# Patch version (1.0.0 -> 1.0.1)
npm version patch

# Minor version (1.0.0 -> 1.1.0)
npm version minor

# Major version (1.0.0 -> 2.0.0)
npm version major

Publication Checklist

• [ ] All tests pass: npm test -- libs/nest-sum
• [ ] Build successful: npm run build:lib
• [ ] Version updated in package.json
• [ ] README.md is up to date
• [ ] Dependencies are correctly specified as peer dependencies
• [ ] NPM account has appropriate permissions

Peer Dependencies

• @nestjs/common: ^10.0.0 || ^11.0.0
• @nestjs/config: ^3.0.0 || ^4.0.0
• @nestjs/core: ^10.0.0 || ^11.0.0
• reflect-metadata: ^0.1.13 || ^0.2.0
• rxjs: ^7.0.0

License

MIT