klona
Advanced tools
Package description
The klona npm package is a JavaScript utility for deep cloning objects. It allows developers to create a deep copy of an object, ensuring that changes to the new object do not affect the original object. This is particularly useful when working with complex data structures or when you need to ensure data immutability.
Deep cloning of objects
This feature allows you to create a deep clone of an object, which means that nested objects are also cloned, and changes to the cloned object do not affect the original object.
{"const klona = require('klona');\nconst original = { a: 1, b: { c: 2 } };\nconst copy = klona(original);\ncopy.b.c = 3;\nconsole.log(original.b.c); // 2\nconsole.log(copy.b.c); // 3"}Deep cloning of arrays
Similar to object cloning, klona can also deep clone arrays, including nested arrays, ensuring that modifications to the cloned array do not affect the original array.
{"const klona = require('klona');\nconst original = [1, [2, 3], [4, 5]];\nconst copy = klona(original);\ncopy[1][0] = 'changed';\nconsole.log(original[1][0]); // 2\nconsole.log(copy[1][0]); // 'changed'"}Cloning class instances
klona is capable of cloning instances of classes, allowing you to duplicate an instance and modify the copy without affecting the original instance.
{"const klona = require('klona');\nclass Example {\n constructor(value) {\n this.value = value;\n }\n}\nconst original = new Example(1);\nconst copy = klona(original);\ncopy.value = 2;\nconsole.log(original.value); // 1\nconsole.log(copy.value); // 2"}Lodash is a popular utility library that includes a `cloneDeep` function for deep cloning objects. It is more feature-rich than klona but also larger in size, which might be a consideration for projects where bundle size is a concern.
deep-copy is another npm package that provides deep cloning functionality. It offers similar capabilities to klona but may have different performance characteristics or API nuances.
rfdc (Really Fast Deep Clone) is a package that focuses on performance for deep cloning objects and arrays. It claims to be faster than other deep cloning methods, which might make it a preferred choice for performance-critical applications.
Readme
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.
$ npm install --save klona
There are multiple "versions" of klona available, which allows you to bring only the functionality you need!
klona/jsonSize (gzip): 240 bytes
Availability: CommonJS, ES Module, UMD
Ability: JSON data types
import { klona } from 'klona/json';
klona/liteSize (gzip): 354 bytes
Availability: CommonJS, ES Module, UMD
Ability: extendsklona/jsonwith support for custom class, Date, and RegExp
import { klona } from 'klona/lite';
klonaSize (gzip): 451 bytes
Availability: CommonJS, ES Module, UMD
Ability: extendsklona/litewith support for Map, Set, DataView, ArrayBuffer, TypedArray
import { klona } from 'klona';
klona/fullSize (gzip): 507 bytes
Availability: CommonJS, ES Module, UMD
Ability: extendsklonawith support for Symbol properties and and non-enumerable properties
import { klona } from 'klona/full';
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"
// }
// }
// }
Returns: typeof input
Returns a deep copy/clone of the input.
Running Node v12.18.3
The benchmarks can be found in the /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 valuesDEFAULT – object with RegExp, Date, Array, Map, Set, custom class, Int8Array, DataView, Buffer valuesFULL – like DEFAULT, but adds Symbol and non-enumerable propertiesImportant: Only candidates that pass validation step(s) are listed.
However,lodashandcloneare kept to highlight important differences.
Note: The
clone/includecandidate refers to itsincludeNonEnumerableoption 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 50,156 ops/sec ±0.32% (93 runs sampled)
lodash x 44,269 ops/sec ±0.48% (94 runs sampled)
rfdc x 202,428 ops/sec ±0.91% (94 runs sampled)
clone x 38,947 ops/sec ±0.34% (97 runs sampled)
clone/include x 25,021 ops/sec ±0.22% (93 runs sampled)
clone-deep x 98,676 ops/sec ±0.20% (93 runs sampled)
deep-copy x 129,432 ops/sec ±0.25% (98 runs sampled)
klona/full x 52,482 ops/sec ±0.26% (98 runs sampled)
klona x 257,905 ops/sec ±0.54% (97 runs sampled)
klona/lite x 301,324 ops/sec ±0.31% (97 runs sampled)
klona/json x 336,300 ops/sec ±0.17% (96 runs sampled)
Benchmark :: LITE
lodash x 35,046 ops/sec ±0.20% (96 runs sampled)
clone x 35,425 ops/sec ±0.46% (93 runs sampled)
clone/include x 22,296 ops/sec ±0.31% (95 runs sampled)
clone-deep x 85,550 ops/sec ±0.25% (97 runs sampled)
klona/full x 46,303 ops/sec ±0.30% (96 runs sampled)
klona x 211,161 ops/sec ±0.19% (99 runs sampled)
klona/lite x 241,172 ops/sec ±0.17% (97 runs sampled)
Benchmark :: DEFAULT
lodash x 48,006 ops/sec ±0.34% (95 runs sampled)
✘ Buffer
✘ Map keys
clone x 91,191 ops/sec ±0.24% (94 runs sampled)
✘ DataView
clone/include x 59,209 ops/sec ±0.28% (96 runs sampled)
✘ DataView
klona/full x 84,333 ops/sec ±0.27% (95 runs sampled)
klona x 208,685 ops/sec ±0.23% (95 runs sampled)
Benchmark :: FULL
lodash x 51,634 ops/sec ±0.44% (94 runs sampled)
✘ Buffer
✘ Map keys
✘ Missing non-enumerable Properties
clone/include x 44,020 ops/sec ±0.31% (93 runs sampled)
✘ DataView
✘ Incorrect non-enumerable Properties
klona/full x 78,217 ops/sec ±0.61% (97 runs sampled)
MIT © Luke Edwards
FAQs
A tiny (240B to 501B) and fast utility to "deep clone" Objects, Arrays, Dates, RegExps, and more!
The npm package klona receives a total of 8,048,850 weekly downloads. As such, klona popularity was classified as popular.
We found that klona demonstrated a not healthy version release cadence and project activity because the last version was released a year ago. It has 1 open source maintainer collaborating on the project.
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