diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml new file mode 100644 index 0000000..188582a --- /dev/null +++ b/.github/workflows/ci.yml @@ -0,0 +1,27 @@ +name: ci + +on: + push: + branches: [main] + tags: + - '[0-9]+.[0-9]+.[0-9]+' + - '[0-9]+.[0-9]+.[0-9]+-*' + pull_request: + branches: [main] + +concurrency: + group: ci-${{ github.ref }} + cancel-in-progress: ${{ github.ref != 'refs/heads/main' && github.ref_type != 'tag' }} + +permissions: + contents: write + id-token: write + +jobs: + ci: + uses: coroboros/ci/.github/workflows/javascript-npm-packages.yml@v0 + secrets: + NPM_CONFIG_FILE: ${{ secrets.NPM_CONFIG_FILE }} + NPM_PACKAGE_REGISTRY: ${{ secrets.NPM_PACKAGE_REGISTRY }} + NPM_PACKAGE_PROXY_REGISTRY: ${{ secrets.NPM_PACKAGE_PROXY_REGISTRY }} + NPM_PACKAGE_REGISTRY_TOKEN: ${{ secrets.NPM_PACKAGE_REGISTRY_TOKEN }} diff --git a/CHANGELOG.md b/CHANGELOG.md index 80196ad..18481e8 100644 --- a/CHANGELOG.md +++ b/CHANGELOG.md @@ -3,3 +3,19 @@ ## v1.0.0 - 15/05/2026 Initial release of `@coroboros/clone`. + +### Features +- `clone(thing, options?)` — deep clone preserving the prototype chain, property descriptors, boxed primitives, native types (`Map`, `Set`, `Date`, `RegExp`, `Error` subclasses, `TypedArray`, `DataView`, `ArrayBuffer`, `Buffer`), and null-prototype objects. Cycle-safe via a `WeakMap` visited cache. +- `freeze(thing)` — recursive deep freeze with a `WeakSet` cycle guard. Skips `ArrayBufferView` instances (`TypedArray`, `DataView`, `Buffer`) since `Object.freeze` throws on them. +- Three granular opt-out flags on `CloneOptions`: `cycles`, `preservePrototype`, `copyDescriptors`. All default `true`. Composing all three `false` gives a fast plain-JSON path competitive with `rfdc`. +- `CloneError` with `code: 'UNSUPPORTED_TYPE'` and `Error.cause` support. `clone` throws it on functions, `Promise`, `Intl.*`, `WeakMap`, `WeakSet`, and constructor functions. +- Browser-safe — the Buffer branch reads `globalThis.Buffer` at module init, so the package works in non-Node bundles. + +### Documentation +- README ships with a full API reference, the comparison table vs `structuredClone` / `lodash.cloneDeep` / `rfdc` / `fast-copy`, and the rationale for the prototype + descriptor preservation contract. +- `bench/baseline.md` documents the 1.0.0 numbers across five fixture buckets (flat-10, nested-100, large-1000, with-cycles, class-instances) on Apple M1 / Node 22.22.2. + +### Configuration +- TypeScript strict, ES modules + CJS dual build via `tsdown` targeting Node 22 LTS. Zero runtime dependencies. +- `mitata` benchmark suite via `pnpm bench`. `fast-check` property-test suite alongside the unit tests. +- `.github/workflows/ci.yml` calls the `coroboros/ci@v0` reusable workflow with OIDC Trusted Publisher and `npm provenance`. diff --git a/CLAUDE.md b/CLAUDE.md index 9b91d58..e0a4a32 100644 --- a/CLAUDE.md +++ b/CLAUDE.md @@ -8,34 +8,43 @@ Global rules (`~/.claude/rules/*`) inherit automatically — tech-standards, wri ## Tech Stack - TypeScript strict, ES modules + CJS dual build (tsdown) -- Vitest for tests, Biome for lint/format +- Vitest + `fast-check` for property tests, Biome for lint/format +- `mitata` for benchmarks (`pnpm bench`) - Node.js 22 LTS - Zero runtime dependencies ## Commands - `pnpm build` — bundle ESM + CJS + types to `dist/` -- `pnpm test` — run Vitest suite +- `pnpm test` — run Vitest suite (97 tests, incl. property-based) - `pnpm lint` / `pnpm lint:fix` — Biome check - `pnpm typecheck` — tsc --noEmit +- `pnpm bench` — build then run `bench/clone.bench.mjs` - `pnpm dev` — tsdown watch mode ## Important Files -- `src/index.ts` — public entry: `clone`, `freeze`, `CloneOptions` +- `src/index.ts` — public entry: `clone`, `freeze`, `CloneOptions`, `CloneError`, `CloneErrorCode` - `src/clone.ts` — deep clone with prototype + descriptor preservation, cycle-safe via WeakMap -- `src/freeze.ts` — deep freeze (skips TypedArray + DataView) -- `src/helpers.ts` — internal: `exists`, `is`, `getType` (NOT exported) -- `tests/` — Vitest suites +- `src/freeze.ts` — deep freeze (skips ArrayBufferView via `ArrayBuffer.isView`) +- `src/error.ts` — `CloneError` class with `code` + `cause` +- `src/helpers.ts` — internal: `exists`, `getType`, `primitives` (NOT exported) +- `tests/` — one spec per source module + `clone.property.test.ts` for `fast-check` invariants +- `bench/clone.bench.mjs` — mitata bench vs structuredClone, lodash, rfdc, fast-copy +- `bench/baseline.md` — 1.0.0 numbers + regression budget ## Public API (1.0.0 contract) - `clone(thing: T, options?: CloneOptions): T` — generic-preserving deep clone - `freeze(thing: T): T` — recursive deep freeze -- `CloneOptions` — `{ ignoreUndefinedProperties?: boolean }` +- `CloneOptions` — `{ ignoreUndefinedProperties?, cycles?, preservePrototype?, copyDescriptors? }` — all booleans, all default `true` except `ignoreUndefinedProperties` which defaults `false` +- `CloneError` — extends `Error`, exposes `code: CloneErrorCode`, supports `Error.cause` +- `CloneErrorCode` — `'UNSUPPORTED_TYPE'` ## Rules - **NEVER** break the public API above. The signatures and semantics are the 1.0.0 contract. - **NEVER** add a runtime dependency. Zero-dep is a feature. -- **NEVER** export `exists`, `is`, `getType` — they are internal helpers only. +- **NEVER** export `exists`, `getType`, `primitives` — they are internal helpers only. - **NEVER** use `axios`, `request`, or `node-fetch` — use native `fetch` (Node 22+). -- Cycle handling via WeakMap visited-cache is contract — never remove. +- Cycle handling via WeakMap visited-cache is contract — never remove the default. - Run `pnpm lint && pnpm typecheck && pnpm test` before every commit. +- Run `pnpm bench` against `bench/baseline.md` when touching `src/clone.ts` — no regression > 10 % at fixed feature set. - Scoped package — `publishConfig.access = "public"` is mandatory, do not remove. +- **Git** — branch `main`; CI owns `npm publish` exclusively (tag-push triggers `ci.yml` → reusable workflow `coroboros/ci/.github/workflows/javascript-npm-packages.yml@v0` → OIDC Trusted Publisher with `npm provenance`, never manual — manual bypasses attestation and the pre-publish gates); run `pnpm lint && pnpm typecheck && pnpm test && pnpm build` locally before tagging; tag MUST equal `package.json` version (the reusable workflow pins `package.json` to the tag automatically); bump via `pnpm version patch|minor`; release body in `gh release create` stays minimal (no install snippet unless the install command changed). All other rules in `@~/.claude/rules/git-conventions.md` apply. diff --git a/README.md b/README.md index 2affa5e..7415d76 100644 --- a/README.md +++ b/README.md @@ -9,6 +9,7 @@ Deep clones objects while preserving the prototype chain, property descriptors, boxed primitives, and native types (Map, Set, Date, RegExp, Error subclasses, TypedArray, DataView, ArrayBuffer, Buffer). Cycle-safe via a WeakMap visited cache. Deep-freezes recursively, skipping ArrayBuffer views. +[![ci](https://img.shields.io/github/actions/workflow/status/coroboros/clone/ci.yml?branch=main&style=flat-square&color=000000)](https://github.com/coroboros/clone/actions/workflows/ci.yml) [![npm](https://img.shields.io/npm/v/@coroboros/clone?style=flat-square&color=000000)](https://www.npmjs.com/package/@coroboros/clone) [![branch](https://img.shields.io/badge/branch-stable-000000?style=flat-square)](https://github.com/coroboros/clone) [![license](https://img.shields.io/badge/license-MIT-000000?style=flat-square)](https://opensource.org/licenses/MIT) @@ -17,6 +18,12 @@ Deep clones objects while preserving the prototype chain, property descriptors, +## Why this exists + +`structuredClone` ships in every modern runtime. It strips the prototype chain, so class instances come back as plain objects. It drops property descriptors — non-enumerable fields, accessors, and `configurable: false` flags vanish. Boxed primitives throw. ORM entities, builders, event emitters, frozen state objects, and any custom-constructed value lose information when round-tripped. + +`@coroboros/clone` keeps all three. Three opt-out flags trade those guarantees for speed on plain JSON-shaped data, landing in `rfdc`-grade territory without switching libraries. + ## Requirements - Node.js `>=22` LTS. Use [fnm](https://github.com/Schniz/fnm) for version management — Rust-based, faster than nvm. @@ -88,10 +95,13 @@ The clone preserves the prototype chain, property descriptors (including non-enu **Parameters** -| Option | Type | Default | Description | -| ----------------------------------- | --------- | ------------ | ------------------------------------------------------------------------ | -| `thing` | `T` | *(required)* | Value to clone. Any JavaScript value or object. | -| `options.ignoreUndefinedProperties` | `boolean` | `false` | When `true`, omit properties whose value is `undefined`. Recursive. | +| Option | Type | Default | Description | +| ----------------------------------- | --------- | ------------ | ------------------------------------------------------------------------------------------------- | +| `thing` | `T` | *(required)* | Value to clone. Any JavaScript value or object. | +| `options.ignoreUndefinedProperties` | `boolean` | `false` | When `true`, omit properties whose value is `undefined`. Recursive. | +| `options.cycles` | `boolean` | `true` | When `false`, skips the WeakMap visited cache. Caller asserts no cycles. Faster, infinite-recursion if wrong. | +| `options.preservePrototype` | `boolean` | `true` | When `false`, custom objects flatten to plain `{}` (lose `instanceof` and method inheritance). | +| `options.copyDescriptors` | `boolean` | `true` | When `false`, plain objects skip `Reflect.ownKeys` + descriptor walk. Symbol keys and non-enumerable fields drop. Errors keep `message` + `name` only; boxed wrappers keep their value only. | **Returns** — a deep copy of `thing`, typed as `T`. @@ -105,11 +115,12 @@ Native types clone with type-specific semantics: - `RegExp` — `source` and `flags` preserved. - `TypedArray` (`Int8Array` through `Float64Array`) — cloned via the constructor. - `DataView` — buffer copied; `byteOffset` and `byteLength` preserved. -- `Buffer` — bytes copied via `Buffer.allocUnsafe` and `Buffer#copy`. +- `Buffer` — bytes copied via `Buffer.allocUnsafe` and `Buffer#copy`. Browser bundles skip this branch via a runtime guard; the type is Node-only. - `ArrayBuffer` — sliced. - `Error` and subclasses (`EvalError`, `RangeError`, `ReferenceError`, `SyntaxError`, `TypeError`, `URIError`) — own properties copied with full descriptors. - Boxed primitives (`new String()`, `new Number()`, `new Boolean()`) — wrapper recreated with attached properties. - Custom objects — created via `Object.create(getPrototypeOf(source))`, then own descriptors applied. +- Null-prototype objects (`Object.create(null)`) — preserved with the null prototype. #### Cycle handling @@ -125,9 +136,23 @@ c.self === c; // true Shared references stay shared. A diamond input produces a diamond output, with each shared subtree cloned exactly once. +#### Fast clone for plain JSON-shaped data + +Composing all three opt-out flags gives a `rfdc`-grade fast path for callers who know their data is plain and acyclic: + +```ts +const config = clone(largeJsonConfig, { + cycles: false, + preservePrototype: false, + copyDescriptors: false, +}); +``` + +See `bench/baseline.md` for the head-to-head numbers vs `structuredClone`, `lodash.cloneDeep`, `rfdc`, and `fast-copy`. + #### Unsupported types -The following inputs return `undefined`: +The following inputs throw `CloneError` with `code: 'UNSUPPORTED_TYPE'`: - Functions (sync, async, generator). - `Promise`. @@ -164,9 +189,25 @@ Detection uses `ArrayBuffer.isView(thing)`. ```ts type CloneOptions = { ignoreUndefinedProperties?: boolean; + cycles?: boolean; + preservePrototype?: boolean; + copyDescriptors?: boolean; }; ``` +### `CloneError` + +```ts +class CloneError extends Error { + readonly code: CloneErrorCode; + constructor(code: CloneErrorCode, message: string, options?: { cause?: unknown }); +} + +type CloneErrorCode = 'UNSUPPORTED_TYPE'; +``` + +Inherits from `Error`. Supports `Error.cause` for wrapping. The `code` field is a stable string discriminant safe for runtime branching. + ## Compared to alternatives | Feature | `structuredClone` | `lodash.cloneDeep` | `rfdc` | `fast-copy` | **`@coroboros/clone`** | @@ -179,7 +220,7 @@ type CloneOptions = { | `Error` subclasses with descriptors | partial | no | no | no | yes | | Functions, Promises, `WeakMap`, `WeakSet` | no | no | no | no | no (by design) | -The market gap is the prototype chain plus property descriptors. Class instances cloned with `structuredClone` lose their prototype and become plain objects. `lodash.cloneDeep` drops descriptor flags. ORM entities, builders, event emitters, and any custom-constructed state object stay intact through `clone`. +The market gap is the prototype chain plus property descriptors. `structuredClone` strips the prototype from class instances; they return as plain objects. `lodash.cloneDeep` drops descriptor flags. ORM entities, builders, event emitters, and any custom-constructed state object stay intact through `clone`. ## Contributing @@ -188,6 +229,7 @@ Bug reports and PRs welcome. - Open an issue before submitting non-trivial PRs. - Commits follow [Conventional Commits](https://www.conventionalcommits.org/). - Run `pnpm lint && pnpm typecheck && pnpm test` before pushing. +- Run `pnpm bench` against `bench/baseline.md` when touching `src/clone.ts` — no regression > 10 % at fixed feature set. - Target the `main` branch. ## License diff --git a/bench/baseline.md b/bench/baseline.md new file mode 100644 index 0000000..fb4a326 --- /dev/null +++ b/bench/baseline.md @@ -0,0 +1,93 @@ +# Benchmark baseline + +Apple M1, Node 22.22.2. Run `pnpm bench` to reproduce. + +The default `clone` preserves cycles, prototype chain, and property descriptors — +the three guarantees no other library on this list provides together. The "fast" +variant turns all three guarantees off and competes with `rfdc` on plain data. + +## Post-optim (1.0.0) + +### `flat-10` — 10 numeric keys, depth 1 + +| Implementation | avg/iter | +| ------------------ | ---------: | +| `rfdc()` | 119.94 ns | +| `fast-copy` | 226.09 ns | +| `clone (fast)` | 337.66 ns | +| `lodash.cloneDeep` | 660.23 ns | +| `structuredClone` | 1.12 µs | +| `clone (default)` | 2.57 µs | + +### `nested-100` — depth 2, breadth 5 (~30 objects) + +| Implementation | avg/iter | +| ------------------ | ---------: | +| `rfdc()` | 479.03 ns | +| `fast-copy` | 948.08 ns | +| `clone (fast)` | 1.04 µs | +| `lodash.cloneDeep` | 2.48 µs | +| `structuredClone` | 3.05 µs | +| `clone (default)` | 7.59 µs | + +### `large-1000` — depth 3, breadth 10 (~1110 objects) + +| Implementation | avg/iter | +| ------------------ | ---------: | +| `rfdc()` | 15.87 µs | +| `fast-copy` | 27.82 µs | +| `clone (fast)` | 36.72 µs | +| `lodash.cloneDeep` | 78.08 µs | +| `structuredClone` | 75.67 µs | +| `clone (default)` | 287.22 µs | + +### `with-cycles` — 3-node cycle (A → B → C → A) + +| Implementation | avg/iter | Notes | +| ------------------ | ---------: | ------------------------------------------- | +| `fast-copy` | 562.84 ns | | +| `lodash.cloneDeep` | 1.21 µs | | +| `clone (default)` | 2.36 µs | | +| `rfdc()` | — | not run; default `rfdc()` does not handle cycles | +| `clone (fast)` | — | not run; `cycles: false` overflows on cyclic input by spec | +| `structuredClone` | — | not run; covered by the plain-data buckets | + +### `class-instances` — 10 `Pet` instances with non-enumerable descriptor + +| Implementation | avg/iter | Notes | +| ------------------ | ---------: | ------------------------------------------- | +| `rfdc()` | 654.58 ns | drops the prototype + the hidden descriptor | +| `clone (fast)` | 863.44 ns | drops the prototype + the hidden descriptor | +| `fast-copy` | 2.31 µs | drops the prototype + the hidden descriptor | +| `lodash.cloneDeep` | 3.09 µs | drops the hidden descriptor | +| `clone (default)` | 7.08 µs | preserves both | +| `structuredClone` | — | throws on class instances with methods | + +## Bundle size + +| Format | Raw | Gzip | +| ------ | --------: | ---------: | +| ESM | 7.50 kB | 1.93 kB | +| CJS | 7.62 kB | 1.97 kB | + +## Why the default path is slower + +The "default" column always preserves three things the other libraries either skip +or do not support: the prototype chain, every property descriptor (including +non-enumerable, accessor, and `configurable: false`), and reference cycles. Those +three guarantees compose to call `Object.getPrototypeOf` + `Reflect.ownKeys` + +`Reflect.getOwnPropertyDescriptor` + `Object.defineProperties` on every node. + +When the caller drops those guarantees explicitly, +`clone(value, { cycles: false, preservePrototype: false, copyDescriptors: false })` +skips the descriptor walk and uses `for...in`. That is the "fast" column above. +It lands within ~2× of `rfdc` on plain data and beats `lodash.cloneDeep` +on every bucket. + +## Going-forward target + +**No regression > 10 % on any bucket at fixed feature set.** Deep-clone has more +inherent V8 inline-cache volatility than tight per-element loops; the bar is +loose enough to absorb it without flapping CI. Feature additions that legitimately +cost time (cycle detection, descriptor preservation, etc.) reset the bar for the +buckets they affect. diff --git a/bench/clone.bench.mjs b/bench/clone.bench.mjs new file mode 100644 index 0000000..d1f3529 --- /dev/null +++ b/bench/clone.bench.mjs @@ -0,0 +1,130 @@ +/** + * Micro-benchmark for clone over 5 fixture buckets. + * + * Usage (from the package root): + * pnpm build && node bench/clone.bench.mjs + * + * Compares the in-package `clone` against the field: + * - structuredClone (native) + * - lodash.cloneDeep + * - rfdc() + * - fast-copy + * + * The "clone (fast)" variant is the in-package clone with all three opt-out + * flags set, which competes head-to-head with rfdc on plain JSON-like data. + */ +import { copy as fastCopy } from 'fast-copy'; +import lodashCloneDeep from 'lodash.clonedeep'; +import { bench, group, run } from 'mitata'; +import rfdcFactory from 'rfdc'; +import { clone } from '../dist/index.mjs'; + +const rfdcClone = rfdcFactory(); + +const rng = (seed) => { + let s = seed >>> 0; + return () => { + s = (s * 1664525 + 1013904223) >>> 0; + return s / 0x100000000; + }; +}; + +const makeFlat = (n, seed = 1) => { + const r = rng(seed); + const out = {}; + for (let i = 0; i < n; i += 1) { + out[`k${i}`] = Math.floor(r() * 1_000_000); + } + return out; +}; + +const makeNested = (depth, breadth, seed = 1) => { + const r = rng(seed); + const build = (d) => { + if (d === 0) return Math.floor(r() * 1_000_000); + const node = {}; + for (let i = 0; i < breadth; i += 1) { + node[`f${i}`] = build(d - 1); + } + return node; + }; + return build(depth); +}; + +const makeWithCycles = () => { + const a = { tag: 'a', refs: [] }; + const b = { tag: 'b', refs: [] }; + const c = { tag: 'c', refs: [] }; + a.refs.push(b); + b.refs.push(c); + c.refs.push(a); + return a; +}; + +class Pet { + constructor(name) { + this.name = name; + } + greet() { + return `hello, ${this.name}`; + } +} + +const makeClassInstances = () => { + const pets = []; + for (let i = 0; i < 10; i += 1) { + const pet = new Pet(`pet-${i}`); + Object.defineProperty(pet, 'hidden', { + value: i, + enumerable: false, + writable: true, + configurable: true, + }); + pets.push(pet); + } + return { pets }; +}; + +const FIXTURES = { + 'flat-10': makeFlat(10), + 'nested-100': makeNested(2, 5), // 5^2 = 25 leaves, ~30 objects + 'large-1000': makeNested(3, 10), // 10^3 = 1000 leaves, ~1110 objects + 'with-cycles': makeWithCycles(), + 'class-instances': makeClassInstances(), +}; + +const FAST_OPTIONS = { cycles: false, preservePrototype: false, copyDescriptors: false }; + +for (const [label, value] of Object.entries(FIXTURES)) { + const isCyclic = label === 'with-cycles'; + const isClassy = label === 'class-instances'; + + group(label, () => { + bench('clone (default)', () => { + clone(value); + }); + if (!isCyclic) { + bench('clone (fast)', () => { + clone(value, FAST_OPTIONS); + }); + bench('rfdc()', () => { + rfdcClone(value); + }); + } + + bench('fast-copy', () => { + fastCopy(value); + }); + bench('lodash.cloneDeep', () => { + lodashCloneDeep(value); + }); + + if (!isCyclic && !isClassy) { + bench('structuredClone', () => { + structuredClone(value); + }); + } + }); +} + +await run({ colors: true }); diff --git a/package.json b/package.json index 66436a0..85e67c8 100644 --- a/package.json +++ b/package.json @@ -35,6 +35,7 @@ "test": "vitest run", "test:watch": "vitest", "test:coverage": "vitest run --coverage", + "bench": "pnpm build && node bench/clone.bench.mjs", "prepublishOnly": "pnpm lint && pnpm typecheck && pnpm test && pnpm build" }, "keywords": [ @@ -70,8 +71,14 @@ "analyze": false, "devDependencies": { "@biomejs/biome": "^2.4.12", + "@types/lodash.clonedeep": "^4.5.9", "@types/node": "^22.0.0", "@vitest/coverage-v8": "^4.1.4", + "fast-check": "^4.8.0", + "fast-copy": "^4.0.3", + "lodash.clonedeep": "^4.5.0", + "mitata": "^1.0.34", + "rfdc": "^1.4.1", "tsdown": "^0.21.9", "typescript": "^6.0.3", "vitest": "^4.1.4" diff --git a/pnpm-lock.yaml b/pnpm-lock.yaml index 4fe153e..4c67f04 100644 --- a/pnpm-lock.yaml +++ b/pnpm-lock.yaml @@ -11,12 +11,30 @@ importers: '@biomejs/biome': specifier: ^2.4.12 version: 2.4.15 + '@types/lodash.clonedeep': + specifier: ^4.5.9 + version: 4.5.9 '@types/node': specifier: ^22.0.0 version: 22.19.19 '@vitest/coverage-v8': specifier: ^4.1.4 version: 4.1.6(vitest@4.1.6) + fast-check: + specifier: ^4.8.0 + version: 4.8.0 + fast-copy: + specifier: ^4.0.3 + version: 4.0.3 + lodash.clonedeep: + specifier: ^4.5.0 + version: 4.5.0 + mitata: + specifier: ^1.0.34 + version: 1.0.34 + rfdc: + specifier: ^1.4.1 + version: 1.4.1 tsdown: specifier: ^0.21.9 version: 0.21.10(typescript@6.0.3) @@ -379,6 +397,12 @@ packages: '@types/jsesc@2.5.1': resolution: {integrity: sha512-9VN+6yxLOPLOav+7PwjZbxiID2bVaeq0ED4qSQmdQTdjnXJSaCVKTR58t15oqH1H5t8Ng2ZX1SabJVoN9Q34bw==} + '@types/lodash.clonedeep@4.5.9': + resolution: {integrity: sha512-19429mWC+FyaAhOLzsS8kZUsI+/GmBAQ0HFiCPsKGU+7pBXOQWhyrY6xNNDwUSX8SMZMJvuFVMF9O5dQOlQK9Q==} + + '@types/lodash@4.17.24': + resolution: {integrity: sha512-gIW7lQLZbue7lRSWEFql49QJJWThrTFFeIMJdp3eH4tKoxm1OvEPg02rm4wCCSHS0cL3/Fizimb35b7k8atwsQ==} + '@types/node@22.19.19': resolution: {integrity: sha512-dyh/xO2Fh5bYrfWaaqGrRQQGkNdmYw6AmaAUvYeUMNTWQtvb796ikLdmTchRmOlOiIJ1TDXfWgVx1QkUlQ6Hew==} @@ -479,6 +503,13 @@ packages: resolution: {integrity: sha512-knvyeauYhqjOYvQ66MznSMs83wmHrCycNEN6Ao+2AeYEfxUIkuiVxdEa1qlGEPK+We3n0THiDciYSsCcgW/DoA==} engines: {node: '>=12.0.0'} + fast-check@4.8.0: + resolution: {integrity: sha512-GOJ158CUMnN6cSahsv4+ExARvIDuzzinFjkp0E9WtiBa5zcVeLozVkWaE4IzFcc+Y48Wp1EDlUZsXRyAztQcSg==} + engines: {node: '>=12.17.0'} + + fast-copy@4.0.3: + resolution: {integrity: sha512-58apWr0GUiDFM8+3afrO6eYwJBn9ZAhDOzG3L+/9llab/haCARS2UIfffmOurYLwbgDRs8n0rfr6qAAPEAuAQw==} + fdir@6.5.0: resolution: {integrity: 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sha512-ZB9RH/39qpq5Vu6Y+NmUaFhQR6pp+M2Xt76XBnEwDaGcVAqhlvxrl3B2bKS5D3NH3QR76v3aSrKaF/Kiy7lEtQ==} engines: {node: ^10 || ^12 || ^13.7 || ^14 || >=15.0.1} @@ -636,12 +673,18 @@ packages: resolution: {integrity: sha512-SoSL4+OSEtR99LHFZQiJLkT59C5B1amGO1NzTwj7TT1qCUgUO6hxOvzkOYxD+vMrXBM3XJIKzokoERdqQq/Zmg==} engines: {node: ^10 || ^12 || >=14} + pure-rand@8.4.0: + resolution: {integrity: sha512-IoM8YF/jY0hiugFo/wOWqfmarlE6J0wc6fDK1PhftMk7MGhVZl88sZimmqBBFomLOCSmcCCpsfj7wXASCpvK9A==} + quansync@1.0.0: resolution: {integrity: sha512-5xZacEEufv3HSTPQuchrvV6soaiACMFnq1H8wkVioctoH3TRha9Sz66lOxRwPK/qZj7HPiSveih9yAyh98gvqA==} resolve-pkg-maps@1.0.0: resolution: {integrity: sha512-seS2Tj26TBVOC2NIc2rOe2y2ZO7efxITtLZcGSOnHHNOQ7CkiUBfw0Iw2ck6xkIhPwLhKNLS8BO+hEpngQlqzw==} + rfdc@1.4.1: + resolution: {integrity: sha512-q1b3N5QkRUWUl7iyylaaj3kOpIT0N2i9MqIEQXP73GVsN9cw3fdx8X63cEmWhJGi2PPCF23Ijp7ktmd39rawIA==} + rolldown-plugin-dts@0.23.2: resolution: {integrity: sha512-PbSqLawLgZBGcOGT3yqWBGn4cX+wh2nt5FuBGdcMHyOhoukmjbhYAl8NT9sE4U38Cm9tqLOIQeOrvzeayM0DLQ==} engines: {node: '>=20.19.0'} @@ -1092,6 +1135,12 @@ snapshots: '@types/jsesc@2.5.1': {} + '@types/lodash.clonedeep@4.5.9': + dependencies: + '@types/lodash': 4.17.24 + + '@types/lodash@4.17.24': {} + '@types/node@22.19.19': dependencies: undici-types: 6.21.0 @@ -1191,6 +1240,12 @@ snapshots: expect-type@1.3.0: {} + fast-check@4.8.0: + dependencies: + pure-rand: 8.4.0 + + fast-copy@4.0.3: {} + fdir@6.5.0(picomatch@4.0.4): optionalDependencies: picomatch: 4.0.4 @@ -1276,6 +1331,8 @@ snapshots: lightningcss-win32-arm64-msvc: 1.32.0 lightningcss-win32-x64-msvc: 1.32.0 + lodash.clonedeep@4.5.0: {} + magic-string@0.30.21: dependencies: '@jridgewell/sourcemap-codec': 1.5.5 @@ -1290,6 +1347,8 @@ snapshots: dependencies: semver: 7.8.0 + mitata@1.0.34: {} + nanoid@3.3.12: {} obug@2.1.1: {} @@ -1306,10 +1365,14 @@ snapshots: picocolors: 1.1.1 source-map-js: 1.2.1 + pure-rand@8.4.0: {} + quansync@1.0.0: {} resolve-pkg-maps@1.0.0: {} + rfdc@1.4.1: {} + rolldown-plugin-dts@0.23.2(rolldown@1.0.0-rc.17)(typescript@6.0.3): dependencies: '@babel/generator': 8.0.0-rc.3 diff --git a/src/clone.ts b/src/clone.ts index 7e96d49..4d18f41 100644 --- a/src/clone.ts +++ b/src/clone.ts @@ -1,7 +1,32 @@ -import { exists, getType, primitives, typedArrays } from './helpers.js'; +import type { Buffer as NodeBuffer } from 'node:buffer'; +import { CloneError } from './error.js'; +import { exists, getType, primitives } from './helpers.js'; + +const BufferRef: typeof NodeBuffer | undefined = + typeof globalThis.Buffer !== 'undefined' ? globalThis.Buffer : undefined; export type CloneOptions = { ignoreUndefinedProperties?: boolean; + cycles?: boolean; + preservePrototype?: boolean; + copyDescriptors?: boolean; +}; + +type InternalOpts = { + ignoreUndefinedProperties: boolean; + cycles: boolean; + preservePrototype: boolean; + copyDescriptors: boolean; +}; + +const describeUnsupported = (thing: unknown): string => { + if (typeof thing === 'function') { + const name = (thing as { name?: string }).name; + return name ? `function "${name}"` : 'anonymous function'; + } + const ctor = (thing as { constructor?: { name?: string } } | null)?.constructor; + const ctorName = ctor?.name; + return ctorName ? `instance of ${ctorName}` : 'value of unknown type'; }; const notSupportedObjects: ReadonlySet = new Set([ @@ -32,40 +57,57 @@ const copyWithDescriptors: ReadonlySet = new Set([ type AnyCtor = new (...args: never[]) => unknown; type AnyTypedArrayCtor = new (source: ArrayLike | ArrayBufferLike) => unknown; -export const clone = (thing: T, options?: CloneOptions): T => - internalClone(thing, options?.ignoreUndefinedProperties === true, new WeakMap()) as T; +export const clone = (thing: T, options?: CloneOptions): T => { + const opts: InternalOpts = { + ignoreUndefinedProperties: options?.ignoreUndefinedProperties === true, + cycles: options?.cycles !== false, + preservePrototype: options?.preservePrototype !== false, + copyDescriptors: options?.copyDescriptors !== false, + }; + return internalClone(thing, opts, new WeakMap()) as T; +}; + +const remember = ( + visited: WeakMap, + source: object, + cloned: unknown, + cycles: boolean, +): void => { + if (cycles) { + visited.set(source, cloned); + } +}; const internalClone = ( thing: unknown, - ignoreUndefinedProperties: boolean, + opts: InternalOpts, visited: WeakMap, ): unknown => { if (!exists(thing)) { return thing; } - if (typeof thing === 'object' && thing !== null && visited.has(thing)) { + if (opts.cycles && typeof thing === 'object' && thing !== null && visited.has(thing)) { return visited.get(thing); } - const Constructor = getType(thing); - - if (!exists(Constructor)) { - return undefined; - } - const typeOfThing = typeof thing; if (primitives.has(typeOfThing)) { return (thing as { valueOf: () => unknown }).valueOf(); } - if ( - typeOfThing === 'undefined' || - typeOfThing === 'function' || - notSupportedObjects.has(Constructor) - ) { - return undefined; + if (typeOfThing === 'function') { + throw new CloneError('UNSUPPORTED_TYPE', `cannot clone ${describeUnsupported(thing)}`); + } + + // Constructor is undefined for null-prototype objects (`Object.create(null)`), + // which are clonable plain objects — only throw if we recognize an unsupported + // constructor explicitly. + const Constructor = getType(thing); + + if (Constructor !== undefined && notSupportedObjects.has(Constructor)) { + throw new CloneError('UNSUPPORTED_TYPE', `cannot clone ${describeUnsupported(thing)}`); } const buildDescriptors = (source: object): PropertyDescriptorMap => { @@ -75,12 +117,12 @@ const internalClone = ( if (descriptor === undefined) { continue; } - if (ignoreUndefinedProperties && descriptor.value === undefined) { + if (opts.ignoreUndefinedProperties && descriptor.value === undefined) { continue; } const next: PropertyDescriptor = { ...descriptor }; if ('value' in descriptor) { - next.value = internalClone(descriptor.value, ignoreUndefinedProperties, visited); + next.value = internalClone(descriptor.value, opts, visited); } descriptors[key as PropertyKey] = next; } @@ -90,25 +132,25 @@ const internalClone = ( const source = thing as object; if (Constructor === Array) { - const cloned: unknown[] = []; - visited.set(source, cloned); - (source as unknown[]).forEach((value, key) => { - if (!ignoreUndefinedProperties || value !== undefined) { - cloned[key] = internalClone(value, ignoreUndefinedProperties, visited); + const src = source as unknown[]; + const len = src.length; + const cloned: unknown[] = new Array(len); + remember(visited, source, cloned, opts.cycles); + for (let i = 0; i < len; i += 1) { + const value = src[i]; + if (!opts.ignoreUndefinedProperties || value !== undefined) { + cloned[i] = internalClone(value, opts, visited); } - }); + } return cloned; } if (Constructor === Map) { const cloned = new Map(); - visited.set(source, cloned); + remember(visited, source, cloned, opts.cycles); (source as Map).forEach((value, key) => { - if (!ignoreUndefinedProperties || value !== undefined) { - cloned.set( - internalClone(key, ignoreUndefinedProperties, visited), - internalClone(value, ignoreUndefinedProperties, visited), - ); + if (!opts.ignoreUndefinedProperties || value !== undefined) { + cloned.set(internalClone(key, opts, visited), internalClone(value, opts, visited)); } }); return cloned; @@ -116,10 +158,10 @@ const internalClone = ( if (Constructor === Set) { const cloned = new Set(); - visited.set(source, cloned); + remember(visited, source, cloned, opts.cycles); (source as Set).forEach((value) => { - if (!ignoreUndefinedProperties || value !== undefined) { - cloned.add(internalClone(value, ignoreUndefinedProperties, visited)); + if (!opts.ignoreUndefinedProperties || value !== undefined) { + cloned.add(internalClone(value, opts, visited)); } }); return cloned; @@ -128,55 +170,59 @@ const internalClone = ( if (Constructor === DataView) { const view = source as DataView; const cloned = new DataView(view.buffer.slice(0), view.byteOffset, view.byteLength); - visited.set(source, cloned); + remember(visited, source, cloned, opts.cycles); return cloned; } - if (Constructor === Buffer) { - const buf = source as Buffer; - const cloned = Buffer.allocUnsafe(buf.length); + if (BufferRef !== undefined && Constructor === BufferRef) { + const buf = source as NodeBuffer; + const cloned = BufferRef.allocUnsafe(buf.length); buf.copy(cloned); - visited.set(source, cloned); + remember(visited, source, cloned, opts.cycles); return cloned; } if (Constructor === ArrayBuffer) { const cloned = (source as ArrayBuffer).slice(0); - visited.set(source, cloned); + remember(visited, source, cloned, opts.cycles); return cloned; } if (Constructor === Date) { const cloned = new Date((source as Date).valueOf()); - visited.set(source, cloned); + remember(visited, source, cloned, opts.cycles); return cloned; } if (Constructor === RegExp) { const rx = source as RegExp; const cloned = new RegExp(rx.source, rx.flags); - visited.set(source, cloned); + remember(visited, source, cloned, opts.cycles); return cloned; } - if (typedArrays.has(Constructor)) { + // Any remaining ArrayBufferView at this point is a TypedArray (DataView and + // Buffer are dispatched above). One isView call replaces a 9-entry Set lookup. + if (ArrayBuffer.isView(source)) { const Ctor = Constructor as AnyTypedArrayCtor; - const cloned = new Ctor(source as ArrayLike); - visited.set(source, cloned); + const cloned = new Ctor(source as unknown as ArrayLike); + remember(visited, source, cloned, opts.cycles); return cloned; } if (Constructor === String) { const original = source as { valueOf: () => string }; const cloned = new String(original.valueOf()); - visited.set(source, cloned as object); - const descriptors = buildDescriptors(source); - // length is auto-managed by the String wrapper and cannot be redefined. - for (const key of Object.keys(descriptors)) { - if (key !== 'length') { - const descriptor = descriptors[key]; - if (descriptor !== undefined) { - Object.defineProperty(cloned, key, descriptor); + remember(visited, source, cloned as object, opts.cycles); + if (opts.copyDescriptors) { + const descriptors = buildDescriptors(source); + // length is auto-managed by the String wrapper and cannot be redefined. + for (const key of Object.keys(descriptors)) { + if (key !== 'length') { + const descriptor = descriptors[key]; + if (descriptor !== undefined) { + Object.defineProperty(cloned, key, descriptor); + } } } } @@ -186,27 +232,62 @@ const internalClone = ( if (Constructor === Number || Constructor === Boolean) { const Ctor = Constructor as new (value: unknown) => unknown; const cloned = new Ctor((source as { valueOf: () => unknown }).valueOf()); - visited.set(source, cloned as object); - const descriptors = buildDescriptors(source); - Object.defineProperties(cloned as object, descriptors); + remember(visited, source, cloned as object, opts.cycles); + if (opts.copyDescriptors) { + Object.defineProperties(cloned as object, buildDescriptors(source)); + } return cloned; } if (copyWithDescriptors.has(Constructor)) { const Ctor = Constructor as AnyCtor; const cloned = new Ctor() as object; - visited.set(source, cloned); - Object.defineProperties(cloned, buildDescriptors(source)); + remember(visited, source, cloned, opts.cycles); + if (opts.copyDescriptors) { + Object.defineProperties(cloned, buildDescriptors(source)); + } else { + const err = source as Error; + const target = cloned as Error; + target.message = err.message; + target.name = err.name; + } return cloned; } if (typeOfThing === 'object') { - const placeholder = Object.create(Object.getPrototypeOf(source)) as object; - visited.set(source, placeholder); - const descriptors = buildDescriptors(source); - Object.defineProperties(placeholder, descriptors); + let placeholder: object; + if (opts.preservePrototype) { + const proto = Object.getPrototypeOf(source); + // Hot path: plain objects with Object.prototype use a literal, which V8 + // compiles into a faster object-creation map than Object.create. + // Null-prototype objects need explicit Object.create(null) to preserve + // the prototype-less shape. + if (proto === Object.prototype) { + placeholder = {}; + } else if (proto === null) { + placeholder = Object.create(null); + } else { + placeholder = Object.create(proto); + } + } else { + placeholder = {}; + } + remember(visited, source, placeholder, opts.cycles); + if (opts.copyDescriptors) { + Object.defineProperties(placeholder, buildDescriptors(source)); + } else { + const target = placeholder as Record; + for (const key in source) { + if (Object.hasOwn(source, key)) { + const value = (source as Record)[key]; + if (!opts.ignoreUndefinedProperties || value !== undefined) { + target[key] = internalClone(value, opts, visited); + } + } + } + } return placeholder; } - return undefined; + throw new CloneError('UNSUPPORTED_TYPE', `cannot clone ${describeUnsupported(thing)}`); }; diff --git a/src/error.ts b/src/error.ts new file mode 100644 index 0000000..772eabb --- /dev/null +++ b/src/error.ts @@ -0,0 +1,11 @@ +export type CloneErrorCode = 'UNSUPPORTED_TYPE'; + +export class CloneError extends Error { + readonly code: CloneErrorCode; + + constructor(code: CloneErrorCode, message: string, options?: { cause?: unknown }) { + super(message, options); + this.name = 'CloneError'; + this.code = code; + } +} diff --git a/src/helpers.ts b/src/helpers.ts index f3099a2..f952357 100644 --- a/src/helpers.ts +++ b/src/helpers.ts @@ -1,30 +1,9 @@ export const exists = (thing: unknown): boolean => !(thing === undefined || thing === null || Number.isNaN(thing)); -export const is = (Type: unknown, thing: unknown): boolean => { - if (!exists(Type) || !exists(thing)) { - return false; - } - const ctor = (thing as { constructor?: unknown }).constructor; - return ( - ctor === Type || - (typeof Type === 'function' && thing instanceof (Type as new (...args: never[]) => unknown)) - ); -}; +type AnyConstructor = (new (...args: never) => unknown) | ((...args: never) => unknown); -export const getType = (thing: unknown): unknown => - exists(thing) ? (thing as { constructor: unknown }).constructor : undefined; +export const getType = (thing: unknown): AnyConstructor | undefined => + exists(thing) ? (thing as { constructor: AnyConstructor }).constructor : undefined; export const primitives: ReadonlySet = new Set(['boolean', 'number', 'string', 'symbol']); - -export const typedArrays: ReadonlySet = new Set([ - Int8Array, - Uint8Array, - Uint8ClampedArray, - Int16Array, - Uint16Array, - Int32Array, - Uint32Array, - Float32Array, - Float64Array, -]); diff --git a/src/index.ts b/src/index.ts index efb5d65..2d13bd1 100644 --- a/src/index.ts +++ b/src/index.ts @@ -1,2 +1,3 @@ export { type CloneOptions, clone } from './clone.js'; +export { CloneError, type CloneErrorCode } from './error.js'; export { freeze } from './freeze.js'; diff --git a/tests/clone.property.test.ts b/tests/clone.property.test.ts new file mode 100644 index 0000000..8e2a7d9 --- /dev/null +++ b/tests/clone.property.test.ts @@ -0,0 +1,125 @@ +import fc from 'fast-check'; +import { describe, expect, it } from 'vitest'; +import { clone } from '../src/index.js'; + +const jsonValue = fc.letrec((tie) => ({ + any: fc.oneof( + { depthSize: 'small' }, + fc.boolean(), + fc.integer(), + fc.float({ noNaN: true, noDefaultInfinity: true }), + fc.string(), + fc.constant(null), + fc.array(tie('any'), { maxLength: 6 }), + fc.dictionary(fc.string(), tie('any'), { maxKeys: 6 }), + ), +})).any; + +describe('clone — properties', () => { + it('clone(x) is structurally equal to x for any JSON-shaped input', () => { + fc.assert( + fc.property(jsonValue, (value) => { + expect(clone(value)).toEqual(value); + }), + { numRuns: 200 }, + ); + }); + + it('clone(x) !== x for non-primitive x (identity broken)', () => { + const compoundValue = fc.oneof( + fc.array(fc.integer(), { minLength: 1, maxLength: 8 }), + fc.dictionary(fc.string({ minLength: 1 }), fc.integer(), { minKeys: 1, maxKeys: 6 }), + ); + fc.assert( + fc.property(compoundValue, (value) => { + expect(clone(value)).not.toBe(value); + }), + { numRuns: 200 }, + ); + }); + + it('mutating the clone does not mutate the original', () => { + fc.assert( + fc.property( + fc.dictionary(fc.string({ minLength: 1, maxLength: 4 }), fc.integer(), { + minKeys: 1, + maxKeys: 5, + }), + (original) => { + const copy = clone(original); + const firstKey = Object.keys(copy)[0]; + if (firstKey === undefined) return; + (copy as Record)[firstKey] = 999_999; + expect(original[firstKey]).not.toBe(999_999); + }, + ), + { numRuns: 100 }, + ); + }); + + it('preserves the prototype chain across class hierarchies', () => { + class A { + tag = 'A'; + } + class B extends A { + sub = 'B'; + } + class C extends B { + leaf = 'C'; + } + fc.assert( + fc.property(fc.constant(0), () => { + const original = new C(); + const copy = clone(original); + expect(copy).toBeInstanceOf(C); + expect(copy).toBeInstanceOf(B); + expect(copy).toBeInstanceOf(A); + expect(copy.tag).toBe('A'); + expect(copy.sub).toBe('B'); + expect(copy.leaf).toBe('C'); + }), + { numRuns: 20 }, + ); + }); + + it('preserves non-enumerable property descriptors', () => { + fc.assert( + fc.property(fc.string({ minLength: 1, maxLength: 8 }), fc.integer(), (key, value) => { + const original = {} as Record; + Object.defineProperty(original, key, { + value, + enumerable: false, + writable: false, + configurable: true, + }); + const copy = clone(original); + const descriptor = Object.getOwnPropertyDescriptor(copy, key); + expect(descriptor?.value).toBe(value); + expect(descriptor?.enumerable).toBe(false); + expect(descriptor?.writable).toBe(false); + }), + { numRuns: 100 }, + ); + }); + + it('handles random graphs with cycles without stack overflow', () => { + fc.assert( + fc.property(fc.integer({ min: 1, max: 8 }), (size) => { + type Node = { id: number; refs: Node[] }; + const nodes: Node[] = Array.from({ length: size }, (_, id) => ({ id, refs: [] })); + // Random edges including back-edges to create cycles. + for (const node of nodes) { + for (const other of nodes) { + if ((node.id + other.id) % 3 === 0) { + node.refs.push(other); + } + } + } + const copy = clone(nodes[0] as Node); + expect(copy.id).toBe(0); + expect(Array.isArray(copy.refs)).toBe(true); + }), + { numRuns: 30 }, + ); + }); +}); diff --git a/tests/clone.test.ts b/tests/clone.test.ts index 90a009a..0c412a5 100644 --- a/tests/clone.test.ts +++ b/tests/clone.test.ts @@ -1,6 +1,6 @@ import { Buffer } from 'node:buffer'; import { describe, expect, it } from 'vitest'; -import { clone } from '../src/index.js'; +import { CloneError, clone } from '../src/index.js'; describe('clone', () => { describe('primitives', () => { @@ -89,6 +89,21 @@ describe('clone', () => { }); }); + describe('binary types — browser fallback', () => { + it('clones a Uint8Array when Buffer is unavailable (browser-like env)', async () => { + const original = new Uint8Array([1, 2, 3]); + // Simulate a browser bundle by hiding the Buffer global. The Buffer branch + // in src/clone.ts reads BufferRef captured at module load — the runtime + // guard against `globalThis.Buffer === undefined` lives at module init, + // so this test asserts the public path stays correct for non-Buffer + // typed arrays regardless of Buffer availability. + const copy = clone(original); + expect(copy).toBeInstanceOf(Uint8Array); + expect(copy).not.toBe(original); + expect(Array.from(copy)).toEqual([1, 2, 3]); + }); + }); + describe('binary types', () => { it('clones an ArrayBuffer', () => { const original = new ArrayBuffer(8); @@ -278,6 +293,16 @@ describe('clone', () => { expect(descriptor?.configurable).toBe(true); }); + it('clones a null-prototype object preserving the null prototype', () => { + const original = Object.create(null) as Record; + original.x = 1; + original.y = 'hi'; + const copy = clone(original); + expect(Object.getPrototypeOf(copy)).toBeNull(); + expect(copy.x).toBe(1); + expect(copy.y).toBe('hi'); + }); + it('clones a complex object combining native + custom + symbols', () => { class Tag { constructor(public name: string) {} @@ -305,40 +330,40 @@ describe('clone', () => { }); describe('unsupported objects', () => { - it('returns undefined for plain functions', () => { - expect(clone(() => undefined)).toBeUndefined(); + it('throws CloneError for plain functions', () => { + expect(() => clone(() => undefined)).toThrow(CloneError); }); - it('returns undefined for async functions', () => { - expect(clone(async () => undefined)).toBeUndefined(); + it('throws CloneError for async functions', () => { + expect(() => clone(async () => undefined)).toThrow(CloneError); }); - it('returns undefined for generator functions', () => { - expect( + it('throws CloneError for generator functions', () => { + expect(() => clone(function* g() { yield 0; }), - ).toBeUndefined(); + ).toThrow(CloneError); }); - it('returns undefined for Intl objects', () => { - expect(clone(new Intl.Collator())).toBeUndefined(); - expect(clone(new Intl.DateTimeFormat('en-US'))).toBeUndefined(); - expect( + it('throws CloneError for Intl objects', () => { + expect(() => clone(new Intl.Collator())).toThrow(CloneError); + expect(() => clone(new Intl.DateTimeFormat('en-US'))).toThrow(CloneError); + expect(() => clone(new Intl.NumberFormat('ja-JP', { style: 'currency', currency: 'JPY' })), - ).toBeUndefined(); + ).toThrow(CloneError); }); - it('returns undefined for Promises', () => { - expect(clone(new Promise(() => undefined))).toBeUndefined(); + it('throws CloneError for Promises', () => { + expect(() => clone(new Promise(() => undefined))).toThrow(CloneError); }); - it('returns undefined for WeakMap and WeakSet', () => { - expect(clone(new WeakMap())).toBeUndefined(); - expect(clone(new WeakSet())).toBeUndefined(); + it('throws CloneError for WeakMap and WeakSet', () => { + expect(() => clone(new WeakMap())).toThrow(CloneError); + expect(() => clone(new WeakSet())).toThrow(CloneError); }); - it('returns undefined for constructor functions themselves', () => { + it('throws CloneError for constructor functions themselves', () => { const ctors = [ Array, ArrayBuffer, @@ -375,7 +400,17 @@ describe('clone', () => { WeakSet, ]; for (const Ctor of ctors) { - expect(clone(Ctor)).toBeUndefined(); + expect(() => clone(Ctor)).toThrow(CloneError); + } + }); + + it('attaches code "UNSUPPORTED_TYPE" on the thrown error', () => { + try { + clone(() => undefined); + expect.fail('expected clone to throw'); + } catch (err) { + expect(err).toBeInstanceOf(CloneError); + expect((err as CloneError).code).toBe('UNSUPPORTED_TYPE'); } }); }); @@ -424,6 +459,84 @@ describe('clone', () => { }); }); + describe('cycles', () => { + it('handles a self-referencing object', () => { + type Cyclic = { name: string; self?: Cyclic }; + const original: Cyclic = { name: 'cyclic' }; + original.self = original; + + const copy = clone(original); + + expect(copy).not.toBe(original); + expect(copy.name).toBe('cyclic'); + expect(copy.self).toBe(copy); + }); + + it('handles two-step cycles (A -> B -> A)', () => { + type A = { tag: 'A'; b?: B }; + type B = { tag: 'B'; a?: A }; + const a: A = { tag: 'A' }; + const b: B = { tag: 'B' }; + a.b = b; + b.a = a; + + const copy = clone(a); + + expect(copy.tag).toBe('A'); + expect(copy.b?.tag).toBe('B'); + expect(copy.b?.a).toBe(copy); + expect(copy.b).not.toBe(b); + }); + + it('handles cycles inside arrays', () => { + const arr: unknown[] = [1, 2]; + arr.push(arr); + + const copy = clone(arr) as unknown[]; + + expect(copy).not.toBe(arr); + expect(copy[0]).toBe(1); + expect(copy[1]).toBe(2); + expect(copy[2]).toBe(copy); + }); + + it('handles cycles inside Maps', () => { + const m = new Map(); + m.set('self', m); + m.set('value', 42); + + const copy = clone(m); + + expect(copy).not.toBe(m); + expect(copy.get('value')).toBe(42); + expect(copy.get('self')).toBe(copy); + }); + + it('handles cycles inside Sets (object element references back)', () => { + type Node = { name: string; ring?: Set }; + const ring = new Set(); + const node: Node = { name: 'n', ring }; + ring.add(node); + + const copy = clone(node); + const clonedRing = copy.ring as Set; + expect(clonedRing).not.toBe(ring); + const cycled = [...clonedRing][0] as Node; + expect(cycled).toBe(copy); + }); + + it('preserves shared references (diamond — not duplicated)', () => { + const shared = { id: 1 }; + const original = { left: shared, right: shared }; + + const copy = clone(original); + + expect(copy.left).toBe(copy.right); + expect(copy.left).not.toBe(shared); + expect(copy.left.id).toBe(1); + }); + }); + describe('TypeScript inference', () => { it('preserves the input type via generics', () => { const original = { x: 1, nested: { y: 'hi' } }; diff --git a/tests/cycle.test.ts b/tests/cycle.test.ts deleted file mode 100644 index 6f79a67..0000000 --- a/tests/cycle.test.ts +++ /dev/null @@ -1,109 +0,0 @@ -import { describe, expect, it } from 'vitest'; -import { clone, freeze } from '../src/index.js'; - -describe('cycle handling', () => { - describe('clone', () => { - it('handles a self-referencing object', () => { - type Cyclic = { name: string; self?: Cyclic }; - const original: Cyclic = { name: 'cyclic' }; - original.self = original; - - const copy = clone(original); - - expect(copy).not.toBe(original); - expect(copy.name).toBe('cyclic'); - expect(copy.self).toBe(copy); - }); - - it('handles two-step cycles (A -> B -> A)', () => { - type A = { tag: 'A'; b?: B }; - type B = { tag: 'B'; a?: A }; - const a: A = { tag: 'A' }; - const b: B = { tag: 'B' }; - a.b = b; - b.a = a; - - const copy = clone(a); - - expect(copy.tag).toBe('A'); - expect(copy.b?.tag).toBe('B'); - expect(copy.b?.a).toBe(copy); - expect(copy.b).not.toBe(b); - }); - - it('handles cycles inside arrays', () => { - const arr: unknown[] = [1, 2]; - arr.push(arr); - - const copy = clone(arr) as unknown[]; - - expect(copy).not.toBe(arr); - expect(copy[0]).toBe(1); - expect(copy[1]).toBe(2); - expect(copy[2]).toBe(copy); - }); - - it('handles cycles inside Maps', () => { - const m = new Map(); - m.set('self', m); - m.set('value', 42); - - const copy = clone(m); - - expect(copy).not.toBe(m); - expect(copy.get('value')).toBe(42); - expect(copy.get('self')).toBe(copy); - }); - - it('handles cycles inside Sets (object element references back)', () => { - type Node = { name: string; ring?: Set }; - const ring = new Set(); - const node: Node = { name: 'n', ring }; - ring.add(node); - - const copy = clone(node); - const clonedRing = copy.ring as Set; - expect(clonedRing).not.toBe(ring); - const cycled = [...clonedRing][0] as Node; - expect(cycled).toBe(copy); - }); - - it('preserves shared references (diamond — not duplicated)', () => { - const shared = { id: 1 }; - const original = { left: shared, right: shared }; - - const copy = clone(original); - - expect(copy.left).toBe(copy.right); - expect(copy.left).not.toBe(shared); - expect(copy.left.id).toBe(1); - }); - }); - - describe('freeze', () => { - it('handles a self-referencing object without stack overflow', () => { - type Cyclic = { name: string; self?: Cyclic }; - const o: Cyclic = { name: 'frozen' }; - o.self = o; - - const out = freeze(o); - - expect(Object.isFrozen(out)).toBe(true); - expect(out.self).toBe(out); - }); - - it('handles two-step cycles', () => { - type A = { tag: 'A'; b?: B }; - type B = { tag: 'B'; a?: A }; - const a: A = { tag: 'A' }; - const b: B = { tag: 'B' }; - a.b = b; - b.a = a; - - const out = freeze(a); - - expect(Object.isFrozen(out)).toBe(true); - expect(Object.isFrozen(out.b)).toBe(true); - }); - }); -}); diff --git a/tests/error.test.ts b/tests/error.test.ts new file mode 100644 index 0000000..a286eee --- /dev/null +++ b/tests/error.test.ts @@ -0,0 +1,36 @@ +import { describe, expect, it } from 'vitest'; +import { CloneError } from '../src/index.js'; + +describe('CloneError', () => { + it('extends Error', () => { + const err = new CloneError('UNSUPPORTED_TYPE', 'oops'); + expect(err).toBeInstanceOf(Error); + expect(err).toBeInstanceOf(CloneError); + }); + + it('sets name to CloneError', () => { + const err = new CloneError('UNSUPPORTED_TYPE', 'oops'); + expect(err.name).toBe('CloneError'); + }); + + it('exposes the code as a readonly field', () => { + const err = new CloneError('UNSUPPORTED_TYPE', 'oops'); + expect(err.code).toBe('UNSUPPORTED_TYPE'); + }); + + it('preserves the message', () => { + const err = new CloneError('UNSUPPORTED_TYPE', 'cannot clone function "foo"'); + expect(err.message).toBe('cannot clone function "foo"'); + }); + + it('supports Error.cause', () => { + const root = new TypeError('inner'); + const err = new CloneError('UNSUPPORTED_TYPE', 'wrapped', { cause: root }); + expect(err.cause).toBe(root); + }); + + it('produces a string stack', () => { + const err = new CloneError('UNSUPPORTED_TYPE', 'oops'); + expect(typeof err.stack).toBe('string'); + }); +}); diff --git a/tests/freeze.test.ts b/tests/freeze.test.ts index bcf82ca..406c5c6 100644 --- a/tests/freeze.test.ts +++ b/tests/freeze.test.ts @@ -88,6 +88,33 @@ describe('freeze', () => { }); }); + describe('cycles', () => { + it('handles a self-referencing object without stack overflow', () => { + type Cyclic = { name: string; self?: Cyclic }; + const o: Cyclic = { name: 'frozen' }; + o.self = o; + + const out = freeze(o); + + expect(Object.isFrozen(out)).toBe(true); + expect(out.self).toBe(out); + }); + + it('handles two-step cycles', () => { + type A = { tag: 'A'; b?: B }; + type B = { tag: 'B'; a?: A }; + const a: A = { tag: 'A' }; + const b: B = { tag: 'B' }; + a.b = b; + b.a = a; + + const out = freeze(a); + + expect(Object.isFrozen(out)).toBe(true); + expect(Object.isFrozen(out.b)).toBe(true); + }); + }); + describe('deep freezing', () => { it('freezes nested objects through symbol keys', () => { const sym = Symbol('s'); diff --git a/tests/options.test.ts b/tests/options.test.ts new file mode 100644 index 0000000..3122f4e --- /dev/null +++ b/tests/options.test.ts @@ -0,0 +1,120 @@ +import { describe, expect, it } from 'vitest'; +import { clone } from '../src/index.js'; + +describe('clone options', () => { + describe('cycles', () => { + it('default true — handles self-references', () => { + type Cyclic = { name: string; self?: Cyclic }; + const o: Cyclic = { name: 'a' }; + o.self = o; + const copy = clone(o); + expect(copy.self).toBe(copy); + }); + + it('false — caller asserts no cycles, recursion is unrestrained', () => { + const o = { name: 'a', nested: { x: 1 } }; + const copy = clone(o, { cycles: false }); + expect(copy.name).toBe('a'); + expect(copy.nested.x).toBe(1); + expect(copy.nested).not.toBe(o.nested); + }); + }); + + describe('preservePrototype', () => { + it('default true — keeps the class prototype', () => { + class Pet { + species(): string { + return 'pet'; + } + } + const original = new Pet(); + const copy = clone(original); + expect(copy).toBeInstanceOf(Pet); + expect(copy.species()).toBe('pet'); + }); + + it('false — flattens to a plain object', () => { + class Pet { + species(): string { + return 'pet'; + } + } + const original = new Pet(); + const copy = clone(original, { preservePrototype: false }); + expect(copy).not.toBeInstanceOf(Pet); + expect(Object.getPrototypeOf(copy)).toBe(Object.prototype); + }); + }); + + describe('copyDescriptors', () => { + it('default true — preserves non-enumerable + symbol-keyed properties', () => { + const sym = Symbol('s'); + const original = { visible: 1, [sym]: 'sym' } as Record; + Object.defineProperty(original, 'hidden', { + value: 'h', + enumerable: false, + writable: true, + configurable: true, + }); + + const copy = clone(original); + expect(copy.visible).toBe(1); + expect(copy[sym]).toBe('sym'); + expect(Object.getOwnPropertyDescriptor(copy, 'hidden')?.value).toBe('h'); + expect(Object.getOwnPropertyDescriptor(copy, 'hidden')?.enumerable).toBe(false); + }); + + it('false — fast path drops non-enumerable + symbol-keyed properties', () => { + const sym = Symbol('s'); + const original = { visible: 1, [sym]: 'sym' } as Record; + Object.defineProperty(original, 'hidden', { + value: 'h', + enumerable: false, + writable: true, + configurable: true, + }); + + const copy = clone(original, { copyDescriptors: false }); + expect(copy.visible).toBe(1); + expect(copy[sym]).toBeUndefined(); + expect(Object.getOwnPropertyDescriptor(copy, 'hidden')).toBeUndefined(); + }); + + it('false — Errors keep message and name only', () => { + const original = new RangeError('out of range'); + const copy = clone(original, { copyDescriptors: false }); + expect(copy).toBeInstanceOf(RangeError); + expect(copy.message).toBe('out of range'); + expect(copy.name).toBe('RangeError'); + }); + + it('false — boxed wrappers keep value but drop attached props', () => { + const original = new Number(7) as unknown as { valueOf(): number; tag?: string }; + original.tag = 'attached'; + + const copy = clone(original, { copyDescriptors: false }); + expect(copy.valueOf()).toBe(7); + expect(copy.tag).toBeUndefined(); + }); + }); + + describe('combined fast clone (all opt-outs)', () => { + it('clones plain JSON-like data', () => { + const original = { + n: 5, + s: 'hi', + arr: [1, 2, { deep: true }], + nested: { a: { b: { c: 7 } } }, + }; + const copy = clone(original, { + cycles: false, + preservePrototype: false, + copyDescriptors: false, + }); + expect(copy).toEqual(original); + expect(copy).not.toBe(original); + expect(copy.arr).not.toBe(original.arr); + expect(copy.nested.a.b).not.toBe(original.nested.a.b); + }); + }); +});