Benchmark: Object.assign vs. JSON String/Parse

Tests:

Spread operator
var n = {foo: 'bar', hello: [{hello: 'world', foo: 'bar'},{hello: 'world', foo: 'bar'},{hello: 'world', foo: 'bar'},{hello: 'world', foo: 'bar'}]}; while(n.length < 1000) { n = [...n]; }
JSON Parse
var n = {foo: 'bar', hello: [{hello: 'world', foo: 'bar'},{hello: 'world', foo: 'bar'},{hello: 'world', foo: 'bar'},{hello: 'world', foo: 'bar'}]}; while(n.length < 1000) { n = JSON.parse(JSON.stringify(n)) }
Object.assign
var n = {foo: 'bar', hello: [{hello: 'world', foo: 'bar'},{hello: 'world', foo: 'bar'},{hello: 'world', foo: 'bar'},{hello: 'world', foo: 'bar'}]}; while(n.length < 1000) { n = Object.assign({}, n); }

Historical Performance Data aggregated from 63 community runs

Desktop Results:

Chrome 51 runs

Object.assign

152.8M/s

JSON Parse

148.5M/s

Spread operator

143.8M/s

View exact numbers

✓ Object.assign: 152,819,648 ops/sec
• JSON Parse: 148,548,896 ops/sec
• Spread operator: 143,846,704 ops/sec

Firefox 7 runs

Object.assign

22.8M/s

JSON Parse

22.8M/s

Spread operator

22.4M/s

View exact numbers

✓ Object.assign: 22,785,218 ops/sec
• JSON Parse: 22,766,788 ops/sec
• Spread operator: 22,358,856 ops/sec

Other 5 runs

Spread operator

94.5M/s

Object.assign

93.2M/s

JSON Parse

91.5M/s

View exact numbers

✓ Spread operator: 94,503,080 ops/sec
• Object.assign: 93,178,272 ops/sec
• JSON Parse: 91,503,160 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
Spread operator
JSON Parse
Object.assign

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 9 months ago)

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/143.0.0.0 Safari/537.36

Browser/OS: Chrome 143 on Mac OS X 10.15.7

View result in a separate tab

Object.assign

70.7M/s

JSON Parse

67.9M/s

Spread operator

30.9M/s

View exact numbers

Test name	Executions per second
✓ Object.assign	70,707,736 Ops/sec
JSON Parse	67,949,432 Ops/sec
Spread operator	30,858,646 Ops/sec

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

LLMs can make mistakes. Check important info.

Let's break down the benchmark definition and test cases.

**Benchmark Definition:**
MeasureThat.net is testing three different approaches to create a new object reference:

1. `Object.assign()`: This function creates a shallow copy of an existing object by merging all its enumerable properties into a new object.
2. JSON String/Parse: This approach uses the `JSON.parse()` and `JSON.stringify()` methods to convert an object to a JSON string, which can then be parsed back into an object.

The test aims to measure the performance difference between these three approaches in creating a new object reference every time.

**Options Compared:**

* **Object.assign()**: This is a built-in JavaScript method that creates a shallow copy of an existing object.
	+ Pros: Fast, efficient, and widely supported.
	+ Cons: Only creates a shallow copy, which means it only copies the top-level properties of the original object. It also modifies the original object if necessary.
* **JSON String/Parse**: This approach converts the object to a JSON string using `JSON.stringify()` and then parses it back into an object using `JSON.parse()`.
	+ Pros: Creates a deep copy of the original object, which means all properties and nested objects are copied recursively. It also does not modify the original object.
	+ Cons: Can be slower than Object.assign() due to the stringification and parsing process.

**Other Considerations:**

* The test uses a while loop to repeat the creation of new object references until a condition is met (in this case, 1000 iterations).
* The test does not account for any potential side effects or memory allocation issues that may arise from creating large numbers of objects.
* The results are likely affected by factors such as JavaScript engine optimizations, hardware, and operating system.

**Library Usage:**
None of the benchmark definitions use external libraries or frameworks. However, it's worth noting that some browsers may have additional features or APIs that can affect the performance of these tests (e.g., `Object.assign()` might be optimized in certain browsers).

**Special JS Feature/Syntax:**
There is no special JavaScript feature or syntax used in these benchmark definitions.

**Alternatives:**

* Other approaches to create a new object reference could include:
	+ Using the spread operator (`{...obj}`) instead of `Object.assign()`.
	+ Using a library like Lodash's `cloneDeep()` function.
	+ Implementing a custom deep copy algorithm using recursion or iteration.

Keep in mind that these alternatives might not be as widely supported or optimized as Object.assign(), and their performance may vary depending on the specific use case and environment.

Object.assign vs. JSON String/Parse (version: 2) Benchmark.js

Creating a "new" object reference every time

Comparing performance of: `Spread operator vs JSON Parse vs Object.assign`

Created: 8 years ago by: Registered User

Go to the latest result

Spread operator

JSON Parse

Object.assign

Historical Performance Data aggregated from 63 community runs

Desktop Results:

Chrome 51 runs

Firefox 7 runs

Other 5 runs

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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

Object.assign vs. JSON String/Parse (version: 2) Benchmark.js

Creating a "new" object reference every time

Comparing performance of: Spread operator vs JSON Parse vs Object.assign

Created: 8 years ago by: Registered User

Go to the latest result

Spread operator

JSON Parse

Object.assign

Historical Performance Data aggregated from 63 community runs

Desktop Results:

Chrome 51 runs

Firefox 7 runs

Other 5 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: `Spread operator vs JSON Parse vs Object.assign`