nest-ndjson-req-stream

Accept and automatically parse NDJSON stream requests in NestJS with Express!

Description

A lightweight library that enables NestJS applications to accept and process streaming NDJSON (Newline Delimited JSON) requests with Express. Perfect for handling large datasets, real-time data feeds, and streaming APIs where each line contains a valid JSON object.

Features

• ✨ Simple decorator-based API for handling NDJSON streams
• 🚀 Memory-efficient processing using AsyncGenerators
• 🎯 TypeScript support with generic types
• 🔧 Configurable batch processing
• 🛡️ Automatic content-type validation
• ⚡ Zero dependencies (only NestJS peer dependencies)

Requirements

• Node.js >= 20.0.0
• NestJS >= 10.0.0
• Express framework

Installation

npm install nest-ndjson-req-stream

Quick Start

Simply use the decorator on request parameters in your controller

import { Controller, Post } from '@nestjs/common';
import { NdJsonStreamReq, NdJsonStreamRequest } from 'nest-ndjson-req-stream';

interface DataItem {
	id: number;
	name: string;
	value: number;
}

@Controller('stream')
export class StreamController {
	@Post('process')
	async processStream(
		@NdJsonStreamReq<DataItem>() request: NdJsonStreamRequest<DataItem>
	) {
		const results: DataItem[] = [];

		// Process each item from the stream
		for await (const item of request.body) {
			// Process your data here
			console.log('Received:', item);
			results.push(item);
		}

		return {
			message: 'Stream processed successfully',
			itemCount: results.length,
		};
	}
}