Benchmark: object create - MeasureThat.net

Tests:

object assign
var obj1 = {foo: 'bar', that: 1, enabled: false}; var obj2 = Object.assign({}, obj1, { enabled: true });
for in
var obj1 = {foo: 'bar', that: 1, enabled: false}; var obj2 = {}; for(var key in obj1) { if(obj1.hasOwnProperty(key)) { obj2[key] = obj1[key]; } } obj2.enabled = true;

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
object assign
for in

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 27 days ago):

LLMs can make mistakes. Check important info.

Let's break down the provided benchmark and explain what is being tested, compared, and discussed.

**Benchmark Definition**

The provided JSON represents the benchmark definition, which includes:

* `Name`: The name of the benchmark ("object create").
* `Description`: None (meaning there's no description provided).
* `Script Preparation Code`: None (meaning no code needs to be executed before running the benchmark).
* `Html Preparation Code`: None (meaning no HTML preparation is required).

This suggests that the benchmark only focuses on measuring the performance of JavaScript object creation and manipulation, without any additional setup or preparation.

**Individual Test Cases**

The benchmark includes two individual test cases:

1. **"object assign"`**
	* The benchmark definition creates two objects: `obj1` with some properties (`foo`, `that`, and `enabled`) and `obj2` using `Object.assign()` to copy the properties from `obj1`. The goal is to measure how fast each browser can create and manipulate these objects.
	* This test compares:
		+ Using `Object.assign()` to create a new object with some properties (`object assign`).
		+ Using a `for...in` loop to iterate over the properties of `obj1` and assigning them to `obj2` individually (`for in`).
2. **"for in"`**
	* The benchmark definition creates two objects: `obj1` with some properties (`foo`, `that`, and `enabled`) and an empty object `obj2`. It then uses a `for...in` loop to iterate over the properties of `obj1` and assign them to `obj2`.
	* This test compares:
		+ Using `Object.assign()` to create a new object with some properties (`object assign`).
		+ Using a `for...in` loop to iterate over the properties of `obj1` and assigning them to `obj2` individually (`for in`).

**Pros and Cons of Each Approach**

* **Using `Object.assign()` (object assign)**:
	+ Pros: Efficient, creates a new object with some properties.
	+ Cons: May not work as expected if the source object is modified while creating the copy.
* **Using a `for...in` loop (for in)**:
	+ Pros: Can handle dynamic property names and can be more memory-efficient than creating multiple objects.
	+ Cons: Slower due to the iteration over properties, which may not be optimal for large datasets.

**Library Used**

In this benchmark, no specific library is used. The tests focus on the basic JavaScript object creation and manipulation methods (`Object.assign()` and `for...in` loop).

**Special JS Features or Syntax**

There are no special features or syntax mentioned in the provided code snippets. However, it's worth noting that some browsers may have additional optimizations or limitations for certain JavaScript features.

**Other Alternatives**

If you're interested in measuring performance benchmarks for other JavaScript-related topics, here are a few alternatives:

* **Benchmarking object size**: Measure how much memory is allocated when creating objects with different properties and sizes.
* **Benchmarking array operations**: Measure the performance of various array operations like indexing, slicing, and concatenation.
* **Benchmarking function calls**: Measure the performance of calling functions with varying numbers of arguments and different types of arguments (e.g., primitive vs. object).

These are just a few examples, but there are many other aspects of JavaScript that can be benchmarked for performance comparison.

Latest run results:

Run details: (Test run date: 2025 years ago)

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:59.0) Gecko/20100101 Firefox/59.0

Browser/OS: Firefox 59 on Windows

View result in a separate tab

Test name	Executions per second
object assign	3376068.2 Ops/sec
for in	16754112.0 Ops/sec

Related benchmarks:

object create (version: 0)

Comparing performance of: object assign vs for in

Created: 6 years ago by: Guest

Jump to the latest result

object assign

for in

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 27 days ago):