fs-extra is a Node.js library that extends the native `fs` module with additional file system operations and promise support. It provides drop-in replacement for `fs` with methods like `copy`, `move`, `remove`, `ensureDir`, `outputFile`, `readJson`, `writeJson`, and more. The library uses `graceful-fs` to prevent EMFILE errors and `universalify` to add promise support to all async methods. It supports both CommonJS and ESM imports. The codebase is well-structured with separate modules for each feature (copy, move, ensure, json, mkdirs, etc.) and comprehensive test coverage. It handles edge cases such as symlinks, permissions, timestamps, cross-device moves, and case-insensitive file systems. The library is actively maintained with frequent releases and supports Node.js 14+.
Kopy is a Kotlin compiler plugin that generates an ergonomic DSL for immutable updates on data classes. It adds `copy`, `set`, `update`, and `updateEach` functions to data classes annotated with `@Kopy`, enabling deep nested property changes without manual `copy` chains. The plugin uses `kotlin.concurrent.atomics.AtomicReference` for thread-safe snapshots and integrates as a Gradle plugin. The codebase is a multi-module Gradle project with a compiler plugin module (`kopy-compiler`), a Gradle plugin module (`kopy-gradle-plugin`), a runtime annotations module (`kopy-runtime`), and a configuration enums module (`kopy-args`). It includes extensive test data for FIR and IR transformations, covering diagnostics, box tests, visibility, inheritance, serialization, and edge cases. The project is actively maintained, with a well-structured architecture and high test coverage.