Benchmark: Object freeze vs normal obj access

Script Preparation code:

const baseObj = { ...[ Array.from({ length: 1000 }, () => Math.random().toString(16).slice(2)) ] }

var obj = Object.assign({}, baseObj);
var frozen = Object.freeze(Object.assign({}, baseObj));

Tests:

Freeze
for (let i = 0; i < 1000; i++) { frozen[i] }
No freeze
for (let i = 0; i < 1000; i++) { obj[i] }

Historical Performance Data aggregated from 40 community runs

Desktop Results:

Chrome 24 runs

No freeze

668K/s

Freeze

141K/s

Fastest: No freeze (4.7x faster)

View exact numbers

✓ No freeze: 667,628 ops/sec
• Freeze: 141,023 ops/sec

Firefox 9 runs

No freeze

1.3M/s

Freeze

1.3M/s

View exact numbers

✓ No freeze: 1,311,236 ops/sec
• Freeze: 1,298,015 ops/sec

Mobile Results:

Chrome 7 runs

No freeze

681K/s

Freeze

182K/s

Fastest: No freeze (3.7x faster)

View exact numbers

✓ No freeze: 680,838 ops/sec
• Freeze: 182,401 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
Freeze
No freeze

Fastest: N/A

Slowest: N/A

Latest run results:

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

User agent: Mozilla/5.0 (X11; Linux x86_64; rv:144.0) Gecko/20100101 Firefox/144.0

Browser/OS: Firefox 144 on Linux

View result in a separate tab

Freeze

1.1M/s

No freeze

1.1M/s

View exact numbers

Test name	Executions per second
✓ Freeze	1,110,167 Ops/sec
No freeze	1,103,458 Ops/sec

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

LLMs can make mistakes. Check important info.

I'll explain the benchmark in detail.

**Benchmark Overview**

The provided JSON represents a JavaScript microbenchmarking test case, which compares the performance of two approaches: freezing an object versus normal object access.

**Benchmark Definition**

The benchmark definition consists of two test cases:

1. "Freeze": This test case uses the `Object.freeze()` method to freeze an object and then iterates over its properties using a `for` loop.
2. "No freeze": This test case does not use `Object.freeze()` and instead directly accesses the object's properties in a `for` loop.

**Options Compared**

The two options being compared are:

* **Freezing an object**: Using `Object.freeze()` to create an immutable object that cannot be modified after creation.
* **Normal object access**: Directly accessing an object's properties without freezing it.

**Pros and Cons of Each Approach**

* **Freezing an object:**
	+ Pros:
		- Provides a predictable and stable environment for benchmarking, as the object's state is frozen in time.
		- Can help identify performance bottlenecks related to object mutation.
	+ Cons:
		- May introduce additional overhead due to the creation of a new object instance and the use of `Object.freeze()`.
* **Normal object access:**
	+ Pros:
		- Does not incur additional overhead compared to normal object access.
		- Can provide more realistic performance measurements, as it reflects real-world usage scenarios.
	+ Cons:
		- May introduce variability in performance results due to the dynamic nature of JavaScript objects.

**Library and Purpose**

The `Object.assign()` method is used to create a shallow copy of an object. The purpose of using this method is to create a new object instance that can be modified independently from the original object, which is then frozen using `Object.freeze()`.

**Special JS Feature or Syntax**

There are no special JavaScript features or syntax mentioned in this benchmark.

**Other Considerations**

When interpreting the benchmark results, consider the following:

* The `ExecutionsPerSecond` value represents the number of iterations performed per second on each test case.
* The benchmark was run on a Chrome 128 browser instance with a Mac OS X 10.15.7 operating system and desktop device platform.
* The "No freeze" test case may exhibit higher performance due to the absence of overhead introduced by freezing an object.

**Alternatives**

Other alternatives for comparing object access performance could include:

* Using `Object.create()` or other techniques to create a new object instance with a similar structure to the original object.
* Using a testing framework like Jest or Mocha, which provide built-in support for benchmarking and performance measurement.

Object freeze vs normal obj access (version: 0) Benchmark.js

Comparing performance of: `Freeze vs No freeze`

Created: 4 years ago by: Guest

Go to the latest result

Freeze

No freeze

Historical Performance Data aggregated from 40 community runs

Desktop Results:

Chrome 24 runs

Firefox 9 runs

Mobile Results:

Chrome 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):

Object freeze vs normal obj access (version: 0) Benchmark.js

Comparing performance of: Freeze vs No freeze

Created: 4 years ago by: Guest

Go to the latest result

Freeze

No freeze

Historical Performance Data aggregated from 40 community runs

Desktop Results:

Chrome 24 runs

Firefox 9 runs

Mobile Results:

Chrome 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: `Freeze vs No freeze`