Benchmark: structuredClone vs spread vs Object.assign()

Script Preparation code:

var oldObj = {
    "single": false,
    "applyOverTaxes": false,
    "discountType": "1",
    "value": 100,
    "minimumAmount": 0,
    "quantity": 1,
    "suffixLength": 8,
    "code": "IF5R0AFX",
    "vertical": true,
    "allowedPaymentMethods": null,
    "allowedBanks": null,
    "types": undefined,
    "partners": "Many",
    "startDate": "2020-10-21T00:00:00.000Z",
    "endDate": "2020-10-21T00:00:00.000Z",
    "applyed": false
}

Tests:

structuredClone()
const newObj = structuredClone(oldObj)
spread syntax
const newObj = {...oldObj}
Object.assign()
const newObj = Object.assign({}, oldObj)

Historical Performance Data aggregated from 61 community runs

Desktop Results:

Chrome 54 runs

spread syntax

36.8M/s

Object.assign()

5.6M/s

structuredClone()

631K/s

Fastest: spread syntax (58.4x faster)

View exact numbers

✓ spread syntax: 36,839,392 ops/sec
• Object.assign(): 5,563,589 ops/sec
• structuredClone(): 630,599 ops/sec

Firefox 7 runs

Object.assign()

13.2M/s

spread syntax

4.1M/s

structuredClone()

388K/s

Fastest: Object.assign() (34.1x faster)

View exact numbers

✓ Object.assign(): 13,236,055 ops/sec
• spread syntax: 4,056,080 ops/sec
• structuredClone(): 387,943 ops/sec

Results show median performance across all community submissions. Run this benchmark yourself to verify on your device.

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
structuredClone()
spread syntax
Object.assign()

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 28 days ago)

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/150.0.0.0 Safari/537.36

Browser/OS: Chrome 150 on Windows

View result in a separate tab

spread syntax

24.6M/s

Object.assign()

2.2M/s

structuredClone()

164K/s

View exact numbers

Test name	Executions per second
✓ spread syntax	24,585,106 Ops/sec
Object.assign()	2,232,440 Ops/sec
structuredClone()	164,035 Ops/sec

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

LLMs can make mistakes. Check important info.

Let's break down what is being tested in the provided JSON.

The benchmark compares three methods for creating a shallow copy of an object:

1. `structuredClone()`: This method was introduced in ECMAScript 2020, and it creates a new object that contains all own property keys and values from the original object.
2. Spread syntax (`{...oldObj}`): This method uses the spread operator to create a new object with the same own properties as the original object.
3. `Object.assign()` (with `{}` as the second argument): This method creates a shallow copy of an object by copying all its own enumerable own properties to a new object.

**Options being compared:**

* `structuredClone()`: A relatively new method introduced in ECMAScript 2020, which creates a new object with all own property keys and values from the original object.
* Spread syntax (`{...oldObj}`): An older method that uses the spread operator to create a new object with the same own properties as the original object.
* `Object.assign()`: A widely supported method for creating shallow copies of objects.

**Pros and Cons:**

1. `structuredClone()`:
	* Pros: Efficient, modern approach, preserves all own property keys and values.
	* Cons: Only available in ECMAScript 2020+ browsers and engines.
2. Spread syntax (`{...oldObj}`):
	* Pros: Simple and widely supported, creates a new object with the same properties as the original.
	* Cons: Can be slower than `structuredClone()` for large objects.
3. `Object.assign()`: 
	* Pros: Widely supported, efficient for small to medium-sized objects.
	* Cons: Creates a shallow copy of only enumerable own properties.

**Library and purpose:**

None mentioned in the provided benchmark definition JSON.

**Special JS feature or syntax:**

1. `structuredClone()` uses the ECMAScript 2020+ standard, which is not widely supported yet.

**Other alternatives:**

If none of these methods are available, you can also use:

* `JSON.parse(JSON.stringify(oldObj))`: This method creates a shallow copy of an object by serializing it to a JSON string and then parsing the string back into an object.
* Manual looping over properties using `Object.keys()`, `forEach()`, and assignment.

Note that these alternatives have different performance characteristics and may not preserve all own property keys and values.

structuredClone vs spread vs Object.assign() (version: 0)

Comparing performance of: `structuredClone() vs spread syntax vs Object.assign()`

Created: 4 years ago by: Guest

Go to the latest result

structuredClone()

spread syntax

Object.assign()

Historical Performance Data aggregated from 61 community runs

Desktop Results:

Chrome 54 runs

Firefox 7 runs

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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

structuredClone vs spread vs Object.assign() (version: 0)

Comparing performance of: structuredClone() vs spread syntax vs Object.assign()

Created: 4 years ago by: Guest

Go to the latest result

structuredClone()

spread syntax

Object.assign()

Historical Performance Data aggregated from 61 community runs

Desktop Results:

Chrome 54 runs

Firefox 7 runs

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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

Related benchmarks

Comparing performance of: `structuredClone() vs spread syntax vs Object.assign()`