JavaScript developers need email extraction from frontend code, JSON API responses, and log files without installing Python or learning a new language. When your entire stack runs on Node.js, switching to Python scripts creates unnecessary complexity and dependency management overhead.

Our Email Extractor for Node.js solves this problem by providing a pure JavaScript implementation with modern async/await syntax, stream processing for large files, built-in JSON parsing for API responses, and a familiar CLI interface that integrates seamlessly into your JavaScript workflow.

Whether you're a frontend developer analyzing React component code, a backend engineer processing API logs, or a build tool integrator automating email extraction in webpack pipelines, this tool brings email extraction to your JavaScript environment.

What is the Node.js Email Extractor?

The Node.js Email Extractor is a pure JavaScript script built for Node.js 14+ that uses modern ES6+ features to extract email addresses from text files, JSON data, and code files. It runs entirely in your Node.js environment without external binaries or Python dependencies.

How it works: The script leverages Node.js fs module for file operations, uses regex patterns to identify email addresses, implements async/await for non-blocking I/O, processes large files with streams to avoid memory issues, validates email syntax, removes duplicates, and exports results to JSON or CSV format for easy integration with JavaScript applications.

What makes this tool unique is its native JavaScript implementation optimized for the Node.js ecosystem. No pip install, no virtual environments, no Python-JavaScript bridge - just npm install (optional) and run. Perfect for JavaScript-first teams who want to keep their toolchain consistent.

Node 14+ Modern JavaScript
0 External Dependencies
JSON Native Format Support

Key Features

Node.js Native

Pure Node.js implementation requiring no Python. Uses only built-in modules (fs, readline, stream) for zero-dependency operation.

Async/Await Support

Modern JavaScript with async/await syntax. Non-blocking I/O for better performance in Node.js applications and build tools.

Stream Processing

Handle large files efficiently using Node.js streams. Process gigabyte files without loading everything into memory.

JSON Parsing

Extract emails from JSON API responses and data structures. Recursively searches nested objects and arrays for email addresses.

CLI Interface

Command-line interface for easy integration into shell scripts and build pipelines. Works with npm scripts and package.json.

NPM Compatible

Install as local package or use as standalone script. Integrate into your project's package.json or run directly with node.

How to Use - Step by Step Guide

Prerequisites

  • Node.js 14 or higher installed on your system
  • No npm packages required - uses only Node.js built-in modules
  • Your data files (text, JSON, logs, etc.)

Step 1: Download the Script

Enter your name and email in the download form on the right sidebar. You'll receive an instant download link to your inbox. The script comes as a .js file ready to run with Node.js.

Step 2: No Installation Needed

Unlike Python scripts, no dependencies or virtual environments needed. Just ensure Node.js is installed:

node --version # Should show v14.0.0 or higher

Step 3: Run the Script

For text files:

node email-extractor.js data.txt

For JSON API responses:

node email-extractor.js --json api-response.json

For multiple files:

node email-extractor.js file1.txt file2.log file3.json

Step 4: Review the Results

The script creates emails.json by default (JavaScript-friendly format) or emails.csv with the --csv flag for compatibility with other tools.

Step 5: Integrate Into Your Workflow

Add to your package.json scripts:

{ "scripts": { "extract-emails": "node email-extractor.js logs/*.txt" } }
Pro Tip: Use the --json flag to output JavaScript-friendly JSON format for easy import in your Node.js apps. Perfect for build pipelines and automation scripts.

Code Preview

Here's a preview of how the script works:

#!/usr/bin/env node /** * Email Extractor for Node.js * Extract and validate email addresses using JavaScript */ const fs = require('fs').promises; const readline = require('readline'); const stream = require('stream'); const EMAIL_REGEX = /\b[A-Za-z0-9._%+-]+@[A-Za-z0-9.-]+\.[A-Z|a-z]{2,}\b/g; async function extractEmailsFromFile(filePath) { const emails = new Set(); const fileStream = require('fs').createReadStream(filePath); const rl = readline.createInterface({ input: fileStream, crlfDelay: Infinity }); for await (const line of rl) { const found = line.match(EMAIL_REGEX); if (found) { found.forEach(email => emails.add(email.toLowerCase())); } } return Array.from(emails).sort(); } // Full implementation with JSON support in downloaded script...

The full script includes JSON parsing, stream processing, progress indicators, and export options. Download it using the form to get the complete version.

Real-World Use Cases

1. Frontend Code Analysis

Scenario: You're auditing a React codebase to find all hardcoded email addresses in components, test files, and configuration. Python isn't in your stack and you want to stay in JavaScript.

Solution: Run this Node.js script on your src/ directory to extract all emails from JSX/TSX files. Integrate it into your pre-commit hooks to prevent hardcoded emails.

2. API Response Parsing (React/Vue Apps)

Scenario: Your frontend app receives JSON responses from APIs containing user data. You need to extract and validate all email addresses from saved API response files for testing.

Solution: Use the --json flag to parse JSON responses and recursively extract emails from nested objects. Perfect for test data generation in Jest or Cypress.

3. Build Tool Integration (webpack, gulp)

Scenario: You're building a webpack plugin to extract contact emails from documentation during the build process. Need JavaScript-native solution.

Solution: Import this script as a module in your webpack config or gulp task. Use async/await to extract emails during build and generate a contact list automatically.

Technical Requirements & Specifications

System Requirements

  • Operating System: Windows 7+, macOS 10.12+, Linux (any modern distro)
  • Node.js Version: Node.js 14.0+ (LTS recommended, ES2020 features required)
  • RAM: 256MB minimum (streams keep memory usage low)
  • Disk Space: 5MB for script

Node.js Built-in Modules Used

  • fs/promises: File system operations with async/await
  • readline: Line-by-line file reading
  • stream: Stream processing for large files
  • path: Cross-platform path handling

Supported Input Formats

  • Plain text files (.txt, .log)
  • JSON files and API responses
  • JavaScript source files (.js, .jsx, .ts, .tsx)
  • Any UTF-8 text format

Performance

  • Process 5,000+ lines per second with streams
  • Memory-efficient: uses <50MB for gigabyte files
  • Async I/O prevents blocking your Node.js event loop

Frequently Asked Questions

Q: Does this support TypeScript?
Yes! The script can read TypeScript files (.ts, .tsx) as plain text and extract emails. For running the script itself in TypeScript, you can use ts-node or compile to JavaScript first.
Q: Can I use this in the browser (frontend JavaScript)?
This script is designed for Node.js (backend) because it uses fs module for file access. For browser usage, you'd need to modify it to work with File API and remove Node.js-specific modules.
Q: How do I install it as an npm package?
The downloaded script includes a package.json. Run "npm link" in the script directory to install globally, or copy it to your project's scripts folder and run with "node scripts/email-extractor.js".
Q: What's the performance compared to Python scripts?
For I/O-bound tasks like file parsing, Node.js performs similarly to Python. The advantage is staying in your JavaScript ecosystem without context switching or managing Python environments.
Q: Does it support ES modules (import/export)?
Yes! The script can be converted to ES modules by changing require() to import statements. Instructions for both CommonJS and ES module usage are included in the download.

Related Email Tools

Complement this tool with other free utilities from Postigo:

Email Extractor CSV

Extract emails from CSV files and spreadsheets
Email Extractor Text

Extract emails from plain text and log files
Email Deduplicator

Remove duplicate emails from your lists across multiple sources
Email Normalizer

Standardize email formats and remove dots/plus signs

Why Choose Postigo Email Tools?

All our email tools are 100% free, open-source, and require no registration. We built these tools for JavaScript developers, by developers. Every script is:

  • Production-ready: Tested in real Node.js environments
  • Well-documented: Clear instructions and code comments
  • Regularly updated: Bug fixes and new features based on user feedback
  • Privacy-focused: All processing happens locally on your computer
  • Professionally supported: Email us with questions anytime

Need more automation? Try Postigo Platform for complete email outreach with pre-warmed SMTP, AI content generation, and smart reply filtering.