A tiny (240B to 501B) and fast utility to "deep clone" Objects, Arrays, Dates, RegExps, and more!

## Features * Super tiny and [performant](#benchmarks) * Deep clone / recursive copies * Safely handles complex data types
_Array, Date, Map, Object, RegExp, Set, TypedArray, and more_ Unlike a "shallow copy" (eg, `Object.assign`), a "deep clone" recursively traverses a source input and copies its _values_ — instead of _references_ to its values — into a new instance of that input. The result is a structurally equivalent clone that operates independently of the original source and controls its own values. > **Why "klona"?** It's "clone" in Swedish.
> **What's with the sheep?** [Dolly](https://en.wikipedia.org/wiki/Dolly_(sheep)). ## Install ``` $ npm install --save klona ``` ## Modes There are multiple "versions" of `klona` available, which allows you to bring only the functionality you need! #### `klona/json` > **Size (gzip):** 240 bytes
> **Availability:** [CommonJS](https://unpkg.com/klona/json/index.js), [ES Module](https://unpkg.com/klona/json/index.mjs), [UMD](https://unpkg.com/klona/json/index.min.js)
> **Ability:** JSON data types ```js import { klona } from 'klona/json'; ``` #### `klona/lite` > **Size (gzip):** 354 bytes
> **Availability:** [CommonJS](https://unpkg.com/klona/lite/index.js), [ES Module](https://unpkg.com/klona/lite/index.mjs), [UMD](https://unpkg.com/klona/lite/index.min.js)
> **Ability:** extends `klona/json` with support for custom class, Date, and RegExp ```js import { klona } from 'klona/lite'; ``` #### `klona` > **Size (gzip):** 451 bytes
> **Availability:** [CommonJS](https://unpkg.com/klona/dist/index.js), [ES Module](https://unpkg.com/klona/dist/index.mjs), [UMD](https://unpkg.com/klona/dist/index.min.js)
> **Ability:** extends `klona/lite` with support for Map, Set, DataView, ArrayBuffer, TypedArray ```js import { klona } from 'klona'; ``` #### `klona/full` > **Size (gzip):** 501 bytes
> **Availability:** [CommonJS](https://unpkg.com/klona/full/index.js), [ES Module](https://unpkg.com/klona/full/index.mjs), [UMD](https://unpkg.com/klona/full/index.min.js)
> **Ability:** extends `klona` with support for Symbol properties and and non-enumerable properties ```js import { klona } from 'klona/full'; ``` ## Usage ```js import { klona } from 'klona'; const input = { foo: 1, bar: { baz: 2, bat: { hello: 'world' } } }; const output = klona(input); // exact copy of original assert.deepStrictEqual(input, output); // applying deep updates... output.bar.bat.hola = 'mundo'; output.bar.baz = 99; // ...doesn't affect source! console.log( JSON.stringify(input, null, 2) ); // { // "foo": 1, // "bar": { // "baz": 2, // "bat": { // "hello": "world" // } // } // } ``` ## API ### klona(input) Returns: `typeof input` Returns a deep copy/clone of the input. ## Benchmarks > Running Node v12.18.3 The benchmarks can be found in the [`/bench`](/bench) directory. They are separated into multiple categories: * `JSON` – compares an array of objects comprised of JSON data types (`String`, `Number`, `null`, `Array`, `Object`) * `LITE` – like `JSON`, but adds `RegExp`, `Date` and `undefined` values * `DEFAULT` – object with `RegExp`, `Date`, `Array`, `Map`, `Set`, custom class, `Int8Array`, `DataView`, `Buffer` values * `FULL` – like `DEFAULT`, but adds `Symbol` and non-enumerable properties > **Important:** Only candidates that pass validation step(s) are listed.
However, `lodash` and `clone` are kept to highlight important differences. > **Note:** The `clone/include` candidate refers to its [`includeNonEnumerable` option](https://www.npmjs.com/package/clone#api) enabled. ``` Load times: lodash/clonedeep 29.257ms rfdc 0.511ms clone 0.576ms clone-deep 2.494ms deep-copy 0.451ms klona/full 0.408ms klona 0.265ms klona/lite 0.308ms klona/json 0.263ms Benchmark :: JSON JSON.stringify x 53,899 ops/sec ±0.76% (92 runs sampled) lodash x 46,800 ops/sec ±0.86% (90 runs sampled) rfdc x 221,456 ops/sec ±0.88% (92 runs sampled) clone x 39,537 ops/sec ±0.68% (92 runs sampled) clone/include x 25,488 ops/sec ±1.06% (88 runs sampled) clone-deep x 99,998 ops/sec ±0.91% (93 runs sampled) deep-copy x 141,270 ops/sec ±0.95% (92 runs sampled) klona/full x 55,016 ops/sec ±0.68% (94 runs sampled) klona x 281,215 ops/sec ±0.77% (93 runs sampled) klona/lite x 318,481 ops/sec ±0.72% (91 runs sampled) klona/json x 334,932 ops/sec ±0.66% (93 runs sampled) Benchmark :: LITE lodash x 36,992 ops/sec ±0.65% (91 runs sampled) clone x 35,974 ops/sec ±1.13% (88 runs sampled) clone/include x 22,609 ops/sec ±1.02% (91 runs sampled) clone-deep x 92,846 ops/sec ±0.66% (93 runs sampled) klona/full x 47,873 ops/sec ±0.83% (88 runs sampled) klona x 226,638 ops/sec ±1.16% (93 runs sampled) klona/lite x 257,900 ops/sec ±0.82% (93 runs sampled) Benchmark :: DEFAULT lodash x 55,914 ops/sec ±0.75% (93 runs sampled) ✘ Buffer ✘ Map keys clone x 92,127 ops/sec ±0.83% (94 runs sampled) ✘ DataView clone/include x 62,052 ops/sec ±0.88% (93 runs sampled) ✘ DataView klona/full x 90,308 ops/sec ±0.68% (89 runs sampled) klona x 230,257 ops/sec ±0.71% (91 runs sampled) Benchmark :: FULL lodash x 60,361 ops/sec ±0.65% (91 runs sampled) ✘ Buffer ✘ Map keys ✘ Missing non-enumerable Properties clone/include x 47,263 ops/sec ±0.85% (93 runs sampled) ✘ DataView ✘ Incorrect non-enumerable Properties klona/full x 82,346 ops/sec ±0.62% (93 runs sampled) ``` ## Related * [dlv](https://github.com/developit/dlv) – safely **read** from deep properties in 120 bytes * [dset](https://github.com/lukeed/dset) – safely **write** into deep properties in 160 bytes * [dequal](https://github.com/lukeed/dequal) – safely check for deep equality in 304 to 489 bytes ## License MIT © [Luke Edwards](https://lukeed.com)