Benchmark: JSON.stringify vs structuredClone, modifications

Script Preparation code:

var MyObject = {
  description: 'Creates a deep copy of source, which should be an object or an array.',
  myNumber: 10,
  myBoolean: true,
  jayson: {
    stringify: 'JSON.stringify() method converts a JavaScript value to a JSON string....',
    parse: 'JSON.parse() method parses a JSON string...'
  }
};

var myCopy = null;

Tests:

JSON.stringify
MyObject.myNumber++; myCopy = JSON.parse(JSON.stringify(MyObject));
structuredClone
MyObject.myNumber++; myCopy = structuredClone(MyObject);

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
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.

Let's dive into the explanation of the provided benchmark.

**Overview**

The benchmark compares two approaches to create a copy of an object: `JSON.stringify` and `structuredClone`. The test case uses a sample object, `MyObject`, which contains nested properties, including a `jayson` property that references another string. The goal is to determine which approach is faster and more efficient.

**Options Compared**

The two options being compared are:

1. **JSON.stringify**
2. **structuredClone**

**Pros and Cons of each approach:**

**JSON.stringify**

* Pros:
	+ Widely supported in most JavaScript engines.
	+ Simple to implement.
* Cons:
	+ Can be slower than `structuredClone` for large objects due to the overhead of serializing and parsing JSON strings.
	+ Can lead to memory leaks if not handled correctly (e.g., using `JSON.parse()` on a string that was previously serialized).

**structuredClone**

* Pros:
	+ Designed specifically for creating deep copies of objects, making it faster and more efficient than `JSON.stringify`.
	+ Reduces the risk of memory leaks by only cloning the object's properties.
* Cons:
	+ Requires support from modern JavaScript engines (e.g., Chrome 119 and later).
	+ May not be supported in older browsers or environments.

**Library/Functionality Used**

In this benchmark, `structuredClone` is used to create a deep copy of the `MyObject`. `structuredClone` is a relatively new function introduced in ECMAScript 2020 (ES2020) as part of the "Object Spread" syntax. It's designed to create a new object with the same properties as an existing one, without serializing or deserializing data.

**Special JS Feature/Syntax**

There are no special JavaScript features or syntaxes being used in this benchmark. However, it's worth noting that `structuredClone` is a relatively new feature that may not be supported in all browsers or environments yet.

**Other Alternatives**

If you need to create a copy of an object without using `structuredClone`, other alternatives include:

1. **Object.assign()**: Can be used to spread properties from one object to another, but it only copies shallowly.
2. **Lodash's `cloneDeep()` function**: A popular utility library that provides a deep cloning function for objects.
3. **Manual implementation using recursion or iteration**: You can implement your own deep copying logic using recursive functions or iterations.

Keep in mind that each alternative has its own trade-offs and may not be as efficient or reliable as `structuredClone`.

Latest run results:

Run details: (Test run date: one year ago)

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/119.0.0.0 Safari/537.36

Browser/OS: Chrome 119 on Mac OS X 10.15.7

View result in a separate tab

Test name	Executions per second
JSON.stringify	510404.5 Ops/sec
structuredClone	261317.2 Ops/sec

Related benchmarks:

JSON.stringify vs structuredClone, modifications (version: 0)

JSON.stringify vs structuredClone

Comparing performance of: JSON.stringify vs structuredClone

Created: one year ago by: Guest

Jump to the latest result

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):