fast-copy is a JavaScript library for performing fast deep copies of objects, including support for circular references. It provides a simple `copy` function and a stricter `copyStrict` mode, and you can also build custom high-performance copiers with `createCopier` to override how specific types like arrays, maps, and sets are duplicated.
Project status
- Actively maintained, upstream updates are recent (latest update v4.0.4 on 2026-07-08, about a month before 2026-08-12), with no evidence of a long dormancy period.
- Update cadence appears steady, with updates roughly every 3-4 months in the last cycle (v4.0.3 on 2026-04-10, v4.0.4 on 2026-07-08), and a longer but not extreme gap previously (v4.0.2 on 2025-12-16).
AI summary generated
Recent updates
v4.0.4
fast-copy 4.0.4 ships micro-optimizations to the object copying implementation, focusing on changing iteration patterns for potentially better performance. The release also includes maintenance build tooling updates and a broad set of development dependency bumps.
v4.0.3
fast-copy v4.0.3 addresses incorrect copying behavior for BigInt typed arrays and updates documentation. The diff primarily changes the internal copier registry to correctly support BigInt64Array and BigUint64Array, adds a regression test for issue #128, and removes a README section about generator copying behavior.
v4.0.2
Release v4.0.2 focuses on preventing Generator and AsyncGenerator values from being cloned or otherwise processed, ensuring they are handled as pass-through references instead. It also removes unused Vite and Vitest configuration files from the repo.
Breakingv4.0.1
Release 4.0.1 is a maintenance and security-focused update that primarily targets TypeScript typing alignment (legacy vs built package outputs) and modernizes the project toolchain. It also updates dependencies for a transitive `glob` vulnerability and bumps `js-yaml` as part of the security remediation.
SecurityFeaturesv4.0.0
Release 4.0.0 introduces a major refactor of fast-copy's public API around createCopier, including a new options object shape (createCache, methods, strict) and an internal options layer. The code diff also removes multiple legacy environment fallbacks and changes the module exports to named exports.
Featuresv4.0.0-beta.3
Release 4.0.0-beta.3 includes a small set of TypeScript definition changes described only as a “fix legacy types”. The code diff indicates multiple public API surface changes in index.d.ts, including export shape and option typing updates.
Featuresv4.0.0-beta.2
Release 4.0.0-beta.2 adds build-time scripts that generate domain-specific TypeScript declaration files for ESM and CJS distributions. The build now produces .d.mts for ESM and .d.cts for CJS and adjusts package.json exports to reference these files.
Featuresv4.0.0-beta.1
Release 4.0.0-beta.1 updates the TypeScript build configuration to use NodeNext module semantics broadly, and Node16 specifically for the CJS build. It also adjusts internal source and test imports to use explicit .ts specifiers, aligning with NodeNext/ESM extension handling.
v4.0.0-beta.0
Release v4.0.0-beta.0 significantly modernizes fast-copy’s internals and public API surface. It removes legacy runtime fallbacks (notably around Symbol and RegExp.flags), reworks copier configuration around a unified createCopier options object, and updates exports toward named imports.
BreakingFeaturesv3.0.2
Release 3.0.2 makes a targeted change to the internal cloning utility to better handle a specific edge case involving an Empty class instance (referenced as coming from fast-querystring). The code change is small, and the release notes only mention this new support.