Open-source alternatives to React Codemod

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

OpenRewrite is an automated refactoring engine and source-to-source migration framework. It uses a lossless semantic tree parser to represent source code as type-aware trees that preserve original whitespace and formatting, enabling precise and deterministic modifications. The project utilizes a declarative refactoring pipeline where sequences of transformations are defined in YAML to resolve breaking changes and technical debt. It features type-aware pattern matching and cross-language model mapping to apply similar refactoring patterns across different programming languages. The framework

The browserify-handbook is a comprehensive documentation guide for Browserify, a CommonJS module bundler and JavaScript build tool. It explains how to compile Node.js style modules into single JavaScript files for execution within web browsers. The guide covers the generation of universal module definition bundles that function across Node, AMD, and browser environments. It also details the use of browser-compatible polyfills for Node.js built-in modules to ensure cross-platform compatibility. The manual describes capabilities for source code transformation, frontend build automation, and we

PostCSS is a CSS post-processor and abstract syntax tree transformation tool that parses stylesheets into a structured tree for programmatic analysis and modification. It functions as a plugin-driven pipeline where JavaScript plugins can modify, insert, or delete nodes to transform styles. The project provides a framework for building a custom plugin ecosystem to extend the CSS language with non-standard features such as loops, conditionals, and shorthand properties. It supports multi-syntax parsing through pluggable parsers and stringifiers, allowing it to process various style formats and c

jscodeshift is a JavaScript AST transformation toolkit and codemod engine designed for large-scale code refactoring and structural migrations. It provides a set of utilities to parse source code into abstract syntax trees, programmatically modify those trees, and convert them back into source text. The tool distinguishes itself by preserving original source formatting and stylistic properties during the transformation process. It utilizes a builder for generating structurally valid AST nodes and integrates interchangeable parsing engines to support different language standards and experimenta

Rollup is an ES module bundler and JavaScript module transpiler. It functions as a build tool that combines JavaScript modules into optimized files and converts modern JavaScript and JSX into various output formats for different runtime environments. The project is distinguished by its static-analysis tree shaking engine, which removes unused code and dead exports to minimize bundle size. It also acts as a code splitting orchestrator, partitioning modules into separate chunks to optimize network requests and load times. The tool provides a hook-based plugin system for extending build logic,

Autoprefixer is a PostCSS plugin and browser compatibility tool that automatically manages vendor prefixes for CSS rules. It functions as an abstract syntax tree transformer that parses CSS to insert required prefixes and remove obsolete ones based on real-time compatibility data. The project differentiates itself by providing a dedicated CSS Grid polyfill, which translates modern Grid syntax into legacy formats for older browser versions. It also allows for granular control through the use of inline CSS comments to selectively enable or disable prefixing for specific rules. The system cover

MJML is a responsive email framework and HTML email compiler that translates simplified semantic markup into complex HTML. It functions as an email template engine designed to produce layouts that render consistently across a wide range of email clients. The system provides a markup validation tool to check structural integrity and syntax before compilation. It also includes a version migration utility to upgrade older template files to newer language versions while preserving content and layout structure. The toolset covers several capability areas, including command-line markup compilation

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

Ivy is a machine learning framework transpiler and model converter designed to translate code and computational graphs between different deep learning ecosystems. It serves as a portability tool for migrating model architectures and logic across competing frameworks to enable flexible deployment. The system achieves cross-framework conversion by utilizing abstract syntax tree analysis to rewrite source code and by employing a computational graph tracer to capture tensor flows and operation sequences during live execution. This process allows for the translation of both high-level model defini

Critical is a tool for extracting and inlining the minimum CSS required to render above-the-fold content. It identifies the styles necessary for the initial visible portion of a page to reduce render-blocking requests and improve page load speed. The project generates resolution-specific stylesheets to optimize the initial paint across different device dimensions. It includes a utility to rebase asset URLs within extracted styles, ensuring that images and fonts load correctly when stylesheets are moved to different directories or content delivery networks. The tool provides a command-line in

Babel is a pluggable JavaScript compiler and transpiler that converts modern ECMAScript syntax into backwards-compatible versions of the language. It functions as an abstract syntax tree manipulator, parsing source code into a hierarchical structure to traverse and modify nodes for custom code transformations. The system utilizes a plugin-driven architecture to apply specific transformation rules and supports presets that bundle multiple plugins into named configuration groups. This enables the transformation of experimental syntax and the injection of non-global polyfills to ensure consisten

UglifyJS2 is a suite of tools designed for parsing, beautifying, mangling, and minifying JavaScript code. It functions by converting source code into an abstract syntax tree to enable programmatic analysis and transformation, and it includes a dedicated generator for creating associated source maps. The project optimizes web production builds by compressing script logic and removing unreachable code. It utilizes name mangling to shorten variable and property names and implements a beautifier to reconstruct compressed scripts into a human-readable layout. The toolset covers broad capability a

This project is a comprehensive manual and educational resource focused on the Babel compiler. It serves as a documentation guide and handbook for understanding the inner workings of JavaScript compilation, specifically regarding the transformation of source code. The material provides a technical walkthrough for developing custom plugins and extensions. It covers the process of creating tailored transformations to modify how JavaScript is parsed and generated. The content encompasses the broader JavaScript compilation workflow, focusing on abstract syntax tree manipulation, code generation,

UglifyJS is a tool for JavaScript code minification, AST manipulation, and source beautification. Its primary purpose is to reduce the file size of JavaScript source code by removing whitespace and shortening variable names to optimize frontend build assets. The project differentiates itself through its ability to programmatically analyze and transform code using abstract syntax trees. It performs constant folding analysis and conditional compilation to eliminate unreachable or redundant code, and it employs a multi-pass compression pipeline to maximize total file size reduction. The tool pr

Black is a deterministic Python code formatter and style guide enforcer. It automatically reformats source code and Jupyter notebook cells into a consistent style to eliminate manual debates over code layout and reduce noise in version control diffs. The tool uses abstract syntax tree analysis to restructure code layout while ensuring that the underlying functional logic remains unchanged. It employs a deterministic engine that produces a single consistent output for any given input, removing subjective styling choices. The system provides capabilities for in-place file mutation, automated s

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

sqlglot is a SQL parser and transpiler that represents queries as abstract syntax trees to enable structural analysis, modification, and semantic transformation. It functions as a dialect translator and query optimizer, converting SQL code between different database engines and simplifying syntax trees through rule-based normalization. The project provides a framework for defining custom SQL dialects by overriding tokenizers, parsers, and generators. It includes a lineage analyzer to track data flow from source tables through complex queries to identify the origin of specific columns. Additi

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

Sweet-core is a JavaScript source-to-source compiler and Lisp-style macro system. It functions as a syntax transformer that extends JavaScript by allowing the definition of custom syntax and operators during the compilation process. The system provides a framework for building domain-specific languages through hygienic, recursive macro expansion and the creation of new language constructs. It distinguishes itself by supporting custom operator definitions with configurable associativity and precedence to control expression evaluation. The compiler includes a specialized module system for mana

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

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

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

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

pyupgrade is a static code modernizer and syntax upgrader for Python. It automatically rewrites source code to implement modern language features and syntax based on a specified target version. The tool focuses on removing technical debt by deleting deprecated imports, compatibility shims, and obsolete version-specific conditional blocks. It also refactors type annotations to use current standards, such as simplified generic aliases and union operators. Its capability surface includes updating standard library usage, optimizing built-in function calls, and converting verbose collection const