Open-source alternatives to Codemod

ts-migrate is an automated migration tool designed to transform JavaScript source code into compiling TypeScript files. It functions as a code migration framework that uses abstract syntax trees to perform large-scale refactoring and structural changes across a project. The tool provides a customizable framework for defining plugin-based transformation rules, allowing for the automation of specific code changes. It includes specialized engines for converting JSDoc type definitions into native TypeScript annotations and a utility for suppressing compiler errors by inserting type assertions or

This is a collection of official extensions for the Rollup bundling process. These plugins serve as module transformers, resolution managers, and bundle optimizers designed to modify how JavaScript modules are processed, resolved, and optimized. The suite provides specialized capabilities for modern web transpilation, converting TypeScript, JSX, Flow, and GraphQL into compatible JavaScript. It distinguishes itself through extensive non-JavaScript asset integration, allowing the import of JSON, YAML, CSV, and image files as JavaScript modules or data URIs, and providing support for bundling We

Comby is a command-line utility designed for structural code search and transformation across diverse programming languages. It functions as a code transformation engine that identifies and modifies source code patterns by utilizing syntax-aware templates, ensuring that operations respect language boundaries such as nested blocks, strings, and comments. The tool distinguishes itself by mapping various programming languages to a unified structural representation, allowing for consistent pattern matching that ignores irrelevant whitespace and formatting. It performs these operations by executin

GritQL is an AST-based code transformation engine and structural search tool. It uses a declarative query language to identify and rewrite source code patterns across multiple programming languages by matching abstract syntax tree nodes rather than literal text. The system functions as an automated refactoring framework for large-scale migrations and API updates. It distinguishes itself by utilizing sequential transformation pipelines and reusable blueprints that can be synced between local environments and remote repositories. The tool covers a broad range of capabilities including static a

GoGoCode is an AST-based code transformation toolkit that enables developers to query, match, and rewrite JavaScript source code using jQuery-style selectors and wildcard patterns. At its core, it provides a programmatic code refactoring library that manipulates parsed AST nodes, allowing precise structural modifications without worrying about formatting differences. The toolkit also functions as a JavaScript AST query engine, finding code patterns through snippet-based matching with wildcards that capture unknown or variable-length fragments. What distinguishes GoGoCode is its callback-drive

Utopia is a development platform for building React components through a visual interface that synchronizes changes directly with underlying source code. It functions as an AST-based code editor and a visual component editor, using abstract syntax tree manipulation to update files while preserving the original formatting and structure. The project features an in-browser module bundler that compiles and executes JavaScript modules directly within the browser to provide immediate feedback without server-side build steps. It also includes a pull request preview tool for inspecting and validating

swift-syntax is a library for parsing, manipulating, and generating Swift source code. It provides a source-accurate abstract syntax tree representation of Swift code, acting as a parser, transformer, and code generator. The project serves as the infrastructure for Swift macro development, enabling the expansion and transformation of source code during compilation. It is used to build compiler tooling for static analysis, formatting, and automated refactoring. The system covers a broad range of source analysis capabilities, including the ability to convert source code into structured trees f

SVGR is a tool that transforms static SVG files into reusable React components for direct rendering within user interface trees. It functions as an AST-based code transformer and build-time asset pipeline, parsing SVG XML into an abstract syntax tree to modify elements before generating JavaScript source code. The project integrates an external optimization engine to strip redundant metadata and minify attributes, ensuring vector images are flexible and easy to style. It uses recursive tree traversal to apply these transformations to all nested graphic elements and employs attribute mapping t

magic-string is a low-level JavaScript library designed for compilers and bundlers to perform source code transformations. It serves as a string transformation utility and source map manipulation library that allows for modifying text while automatically tracking character offsets. The library enables the modification of source code strings through insertions, replacements, and removals without losing the relationship to original source positions. It specifically provides mechanisms to generate mapping files that link transformed output text back to original source file coordinates. Capabili

Include What You Use is a C++ include optimizer and header dependency analyzer. It identifies unused or missing header includes in source files to reduce project bloat and improve compilation performance. The tool performs static analysis using a Clang-based abstract syntax tree to map symbol usage and track preprocessor effects across different build configurations. It can automatically rewrite source files by inserting or deleting preprocessor directives based on the calculated dependency graph. The system integrates with compilation databases to determine the exact compiler flags used for

Remark is a markdown processor that parses markdown text into a structured JSON abstract syntax tree for programmatic analysis and transformation. It functions as a markdown AST parser and processor, utilizing a plugin framework to manage extensible syntax and transformation rules. The project enables custom markdown syntax extensions and content transformation through a plugin system, allowing for the addition of non-standard markup and metadata. It also includes a markdown linter to identify style inconsistencies and ensure adherence to writing standards. The toolset covers markdown docume

This is a TC39 proposal to add declarative pattern matching syntax to the ECMAScript language. It introduces a match expression that allows developers to inspect and branch on data structures using patterns with destructuring, guards, and logical combinators. The proposal defines a custom matcher protocol via a well-known symbol, enabling objects to implement user-defined matching logic with arbitrary extraction and decomposition. The proposal supports matching against literal primitives using SameValue equality with special handling for signed zero and NaN, as well as relational comparison

unplugin-auto-import is a build-time import automation plugin and AST-based code transformer. It analyzes source code to identify missing identifiers and automatically injects the required import statements during the bundling process. The project functions as a cross-bundler build plugin, providing a unified abstraction layer that ensures consistent behavior across Vite, Webpack, and Rollup. It utilizes a pattern-based module resolver to scan local directories via glob patterns and employs a TypeScript declaration generator to maintain type definition files for IDE autocompletion. Its capab

Reason is a strongly typed functional language and multi-target compiler designed to produce either JavaScript for web environments or native machine code for operating systems. It serves as an OCaml-compatible language that shares an abstract syntax tree with OCaml, providing a practical syntax for the OCaml ecosystem. The project functions as a type-safe frontend language, incorporating JSX support to build user interfaces through structural elements that translate into type-safe function calls. It enables deep integration with the JavaScript ecosystem, allowing the use of existing librarie

Rector is an automated PHP refactoring and modernization tool designed to upgrade language versions and modernize syntax using predefined rules. It functions as a static analysis engine that inspects code structures and types to identify refactoring targets without executing the code. The project provides a framework for defining custom transformation logic to automate project-specific changes. It distinguishes itself by offering specialized capabilities for migrating legacy or custom frameworks to modern alternatives and converting docblock annotations into native language attributes. The s

Vis is a terminal-based modal text editor that utilizes vi keybindings and a system of structural regular expressions. It functions as a scriptable environment where Lua is used for configuration, custom key mappings, and plugin development. The editor distinguishes itself through a syntax highlighting system based on Parsing Expression Grammars and a pattern matching engine that treats text as a structure for complex search and replace operations. It also integrates directly with the system shell, allowing users to pipe text ranges to external commands and capture the resulting output. The

Recast is a JavaScript AST parser and printer designed for automated code refactoring. It converts source code into abstract syntax trees that can be modified and then printed back into source code. The project focuses on formatting-preserving transformations, storing original whitespace and indentation metadata within syntax tree nodes to reconstruct code without losing its original layout. It also generates character-level source maps to maintain precise correspondences between original input and transformed output. The toolkit includes utilities for syntax tree manipulation using a visito

Memgraph is an in-memory, distributed graph database designed for high-performance labeled property graph management. It utilizes a Cypher query engine for declarative data retrieval and manipulation, providing a scalable knowledge graph backend that integrates vector search and graph traversals. The system distinguishes itself as a real-time graph analytics platform, employing native C++ and CUDA implementations to execute complex network analysis and dynamic community detection on streaming data. It provides specialized support for AI integration, including GraphRAG capabilities, the constr

Metro is a JavaScript bundler designed for React Native environments. It functions as a system for resolving dependencies, transforming source code, and packaging JavaScript and assets into bundles for execution. The project includes a development bundler server that hosts assets via HTTP and provides hot module replacement. It features a module resolver that handles platform-specific file extensions and a source code transformer that converts code into tree structures for optimization and minification. The toolset covers programmatic bundle generation, source map creation, and file system c

This project is an AST-based code optimizer and compressor for modern ECMAScript, JSX, and TypeScript source code. It functions as a JavaScript minifier that uses the Babel toolchain to reduce file size by removing unnecessary characters and whitespace while preserving program logic. The tool is distinguished by its ability to process experimental language proposals and transform modern syntax into browser-compatible versions. It provides specialized handling for React JSX transpilation and strips type annotations from TypeScript files to produce compressed production assets. The system cove

JavaParser is a library that parses Java source code up to version 12 into an Abstract Syntax Tree (AST), enabling programmatic analysis, transformation, and generation of Java code. It serves as a parser, code analyzer, code generator, comment parser, and symbol resolver, providing a unified toolkit for working with Java source at the AST level. The library distinguishes itself through several integrated capabilities that go beyond basic parsing. It includes a symbol resolution engine that resolves type and symbol references across files for accurate semantic analysis, and an error-recovery

Melty is an AI-powered integrated development environment that uses a chat-based interface to automate large-scale code modifications and project management. It functions as an LLM code editor where natural language conversations are used to analyze project structures and apply changes across multiple files. The editor integrates directly with version control to link automated modifications to specific git commits, associating conversation logs with commit history to enable atomic reverts and branching. It further connects the development workspace to local system tools, including shells, com

Helix is a terminal-based modal text editor designed for efficient code manipulation and navigation. It centers on a selection-first editing model, where operations are performed on active ranges rather than individual cursor positions, allowing for precise control over text and code structures. The editor distinguishes itself through deep integration with structural parsing and language intelligence. By utilizing an incremental parsing library, it builds concrete syntax trees that enable advanced features like structural code navigation, intelligent indentation, and syntax-aware text object

This tool is a command-line utility designed to automatically detect and correct coding standard violations in PHP source files. It functions as a static analysis and refactoring engine that ensures consistent project-wide formatting by applying predefined community conventions or custom organizational rules. The project distinguishes itself through a modular rule-based engine that supports both automated style correction and codebase modernization. It allows developers to update legacy syntax to align with newer language versions and testing framework requirements, facilitating the adoption

This project is a technical handbook and tutorial guide for the Babel compiler. It serves as a resource for configuring the tool and writing custom plugins to transform JavaScript source code. The guide provides instructional material on creating custom transformation plugins and modifying the compilation process. It specifically covers how to navigate and modify abstract syntax trees to programmatically rewrite source code. The documentation covers the mechanics of code transformation, the management of compiler configurations, and the fundamentals of compiler tooling. It includes guidance

MonkeyType is a runtime type inferencer and analysis tool for Python. It collects actual argument and return types from function calls during program execution to automate the production of static type annotations and compatible stub files. The system converts captured execution traces into static type hints, which can be inserted directly into source code function definitions or used to generate external type stubs. This process allows for the addition of type safety to existing codebases by analyzing real-world data types rather than through manual auditing. The tool's capabilities cover r

ansible-lint is a static code analysis tool and linter designed to identify syntax errors and best practice violations within Ansible playbooks and roles. It functions as a quality gate for automation pipelines, scanning configuration files and scripts without executing the code to ensure reliability and consistency. The project distinguishes itself by acting as an automated code formatter that can correct identified linting issues and reformat files to meet community standards. It also serves as a dependency manager, automatically detecting and installing required roles and collections from