js2coffee
Parse JavaScript code into Abstract Syntax Trees in real-time
Quick Examples
JavaScript Input
AST Output
Parse JavaScript to see the AST...
What is Esprima?
Esprima is a high-performance, standards-compliant ECMAScript parser written in JavaScript. It produces an Abstract Syntax Tree (AST) following the ESTree specification, making it perfect for code analysis, transformation, and tooling.
Key Features
- Full support for ECMAScript 2020 (ES11)
- Sensible syntax tree format compatible with Mozilla Parser API
- Optional tracking of syntax node location
- Heavily tested with over 1500 unit tests
Use Cases
- Code analysis and linting tools
- JavaScript minifiers and compressors
- Source-to-source compilers and transpilers
- Code coverage and instrumentation
Getting Started
Simply paste your JavaScript code in the input panel above and click "Parse JavaScript" to see the resulting Abstract Syntax Tree. The parser will validate your code and show any syntax errors.
New to AST parsing? Check out our About page to learn more about Esprima, or explore our code examples to see practical use cases. For detailed API information, visit our documentation.
Why Use an AST Parser?
Code Analysis
Understand code structure and complexity by analyzing the syntax tree programmatically.
Code Transformation
Modify and transform JavaScript code safely by manipulating the AST structure.
Syntax Validation
Validate JavaScript syntax and catch errors before runtime execution.
Static Analysis
Build linters, formatters, and other static analysis tools with accurate parsing.
How js2coffee Helps You
Powerful JavaScript parsing made simple and accessible
Instant Code Visualization
See the internal structure of your JavaScript code in real-time. No installation required, just paste your code and get immediate insights into how JavaScript interprets your syntax.
Learn JavaScript Internals
Perfect for students and developers learning JavaScript. Understanding AST helps you grasp how JavaScript engines parse and execute code, making you a better programmer.
Debug Complex Code
Identify syntax issues and understand complex code structures. The AST representation helps you spot problems that might be hidden in nested or convoluted code patterns.
Build Better Tools
Test your AST-based tools and libraries. Whether you're building a linter, formatter, or code analyzer, js2coffee provides a quick way to verify your AST parsing logic.
Validate Syntax Instantly
Quickly check if your JavaScript code is syntactically valid. Get detailed error messages with line and column numbers to fix issues fast.
Free and Privacy-Focused
All parsing happens in your browser. Your code never leaves your machine, ensuring complete privacy. No sign-up, no tracking, no limits.
Who Benefits from js2coffee?
JavaScript Developers
Understand how your code is parsed and structured. Debug complex expressions, validate syntax, and improve your understanding of JavaScript fundamentals.
- Validate code syntax before deployment
- Learn about operator precedence and evaluation order
- Understand scope and hoisting through AST structure
Students & Educators
An invaluable teaching tool for computer science courses. Visualize how JavaScript code is broken down into tokens and nodes, making abstract concepts concrete.
- Teach compiler design and parsing concepts
- Demonstrate the difference between syntax and semantics
- Show how expressions are evaluated step by step
Tool Developers
Build and test tools that manipulate JavaScript code. Perfect for developing linters, formatters, transpilers, and code analysis tools.
- Prototype AST manipulation logic
- Test pattern matching for code analysis
- Verify AST node structures for your tools
Code Reviewers
Analyze complex or unfamiliar code structures during code reviews. The AST view helps you understand what the code actually does, beyond surface-level reading.
- Identify potential security vulnerabilities
- Understand complex nested structures
- Verify code follows expected patterns
Ready to Parse Your JavaScript?
Start using js2coffee now. No installation, no configuration, just paste your code and explore the AST.