Benchmark: Deep copy comparison gil

Tests:

spread ...
const arr1 = {"in":1,"inT":1716588594541,"keep":1,"kind":4,"lastEvtT":1716588594541,"name":"gil","oTips":{"amt":1,"stta":1,"count":1,"lastT":1716588594541,"amtEver":1},"outT":1716588594541,"sex":"m","spanT":0}; const arr2 = { ...arr1 };
JSON.parse(JSON.stringify())
const arr1 = {"in":1,"inT":1716588594541,"keep":1,"kind":4,"lastEvtT":1716588594541,"name":"gil","oTips":{"amt":1,"stta":1,"count":1,"lastT":1716588594541,"amtEver":1},"outT":1716588594541,"sex":"m","spanT":0}; const arr2 = JSON.parse(JSON.stringify(arr1));
structuredClone()
const arr1 = {"in":1,"inT":1716588594541,"keep":1,"kind":4,"lastEvtT":1716588594541,"name":"gil","oTips":{"amt":1,"stta":1,"count":1,"lastT":1716588594541,"amtEver":1},"outT":1716588594541,"sex":"m","spanT":0}; const arr2 = structuredClone(arr1);

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
spread ...
JSON.parse(JSON.stringify())
structuredClone()

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated one month ago):

LLMs can make mistakes. Check important info.

I'll break down the provided benchmark definitions and explain what's being tested, the options compared, their pros and cons, and other considerations.

**Benchmark Context**
MeasureThat.net is a website that allows users to create and run JavaScript microbenchmarks. The website provides a way to test various aspects of JavaScript performance, including object creation, comparison, and cloning methods.

**Benchmark Definition JSON**
The provided benchmark definition JSON contains three test cases:

1. "spread ..."
2. "JSON.parse(JSON.stringify())"
3. "structuredClone()"

Each test case represents a different approach for deep copying an object in JavaScript.

**Test Case 1: Spread Operator**

```javascript
const arr1 = {\"in\":1,\"inT\":1716588594541,\"keep\":1,\"kind\":4,\"lastEvtT\":1716588594541,\"name\":\"gil\",\"oTips\":{\"amt\":1,\"stta\":1,\"count\":1,\"lastT\":1716588594541,\"amtEver\":1},\"outT\":1716588594541,\"sex\":\"m\",\"spanT\":0};\r\nconst arr2 = { ...arr1 };
```

**Test Case 2: JSON.parse(JSON.stringify())**

**Test Case 3: structuredClone()**

**Options Compared**

* `Spread Operator` (`{ ...arr1 }`)
* `JSON.parse(JSON.stringify())`
* `structuredClone()` (new in ECMAScript 2022)

**Pros and Cons:**

* **Spread Operator**:
	+ Pros: Simple, efficient, and widely supported.
	+ Cons: Not all objects are cloned correctly (e.g., functions, dates).
* **JSON.parse(JSON.stringify())**:
	+ Pros: Works for most object types, including arrays and JSON objects.
	+ Cons: Can be slow for large objects, as it involves parsing and re-parsing the JSON representation. Additionally, this method can be vulnerable to certain attacks (e.g., exploiting the `Object.prototype`).
* **structuredClone()**:
	+ Pros: New in ECMAScript 2022, designed specifically for deep cloning objects.
	+ Cons: Still a relatively new feature, and not all browsers support it. Additionally, its performance may vary depending on the specific use case.

**Other Considerations**

* The test cases focus on the performance of each cloning method, rather than their correctness or semantic implications.
* The benchmark results are provided for Chrome 125, running on a Mac OS X 10.15.7 machine.

**Alternatives**
For those interested in exploring alternative methods for deep copying objects in JavaScript:

* **Lodash's `cloneDeep()` function**: A popular library providing a robust and efficient cloning mechanism.
* **Underscore.js's `_clone()` function**: Another well-known library offering a convenient cloning solution.
* **Manual object creation using constructors or `Object.assign()```

Latest run results:

Run details: (Test run date: 6 months ago)

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/125.0.0.0 Safari/537.36

Browser/OS: Chrome 125 on Mac OS X 10.15.7

View result in a separate tab

Test name	Executions per second
spread ...	33551980.0 Ops/sec
JSON.parse(JSON.stringify())	809628.0 Ops/sec
structuredClone()	613758.5 Ops/sec

Related benchmarks:

Deep copy comparison gil (version: 0)

Benchmarks for StackOverflow question on deep copy techniques https://stackoverflow.com/questions/7486085/copy-array-by-value/23536726#23536726

Comparing performance of: spread ... vs JSON.parse(JSON.stringify()) vs structuredClone()

Created: 6 months ago by: Guest

Jump to the latest result

spread ...

JSON.parse(JSON.stringify())

structuredClone()

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated one month ago):