Benchmark: Object.assign vs direct assignment Mutation2

Script Preparation code:

var data = {};

Tests:

Direct Assignment
for(var i = 0; i < 10000; i++) { data[`prop_${i}`] = true; }
Object.assign
let obj = {} for(var i = 0; i < 10000; i++) { var propName = `prop_${i}`; obj[propName]=true; } data={data,...obj}

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Direct Assignment
Object.assign

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 3 years ago)

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/90.0.4430.212 Safari/537.36

Browser/OS: Chrome 90 on Windows

View result in a separate tab

Test name	Executions per second
Direct Assignment	555.3 Ops/sec
Object.assign	182.7 Ops/sec

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

LLMs can make mistakes. Check important info.

Let's break down the provided benchmark and explain what's being tested.

**What is being tested?**

The benchmark is comparing two approaches to assign properties to an object:

1. **Direct Assignment**: This approach uses the `=` operator to directly assign values to the object's properties, like this: `data[`prop_${i}`] = true;`
2. **Object.assign**: This approach uses the `Object.assign()` method to copy and assign properties from one object to another.

**Options compared**

The benchmark is comparing these two approaches, specifically in terms of their performance (expressed as executions per second).

**Pros and Cons**

Here are some pros and cons of each approach:

**Direct Assignment:**

Pros:

* Simplistic and easy to understand
* Does not require importing any additional libraries

Cons:

* May be slower due to the overhead of parsing the property names and performing the assignment
* Can lead to issues if the object's properties have complex or dynamic names

**Object.assign:**

Pros:

* Efficiently copies properties from one object to another
* Supports deep copying, which can be useful for more complex objects

Cons:

* Requires importing the `Object` library (in modern browsers)
* May incur additional overhead due to the method call and parameter passing

**Other considerations**

The benchmark does not take into account other factors that might affect performance, such as:

* The size of the object being assigned properties to
* The type of data being assigned (e.g., numbers vs. strings)
* The presence of any complex or nested objects within the assignment

**Library usage**

In this benchmark, the `Object` library is used for the `Object.assign()` method.

**Special JS feature or syntax**

There are no special JavaScript features or syntaxes being tested in this benchmark. Both approaches use standard JavaScript syntax and do not rely on any experimental or deprecated features.

**Alternatives**

If you wanted to modify or extend this benchmark, here are some alternative approaches you could consider:

* **Using a different assignment method**: Instead of `Object.assign()`, you could try using other methods like `for...in` loops or the spread operator (`{ ...data }`)
* **Adding additional complexity**: You could add more complex objects or nested assignments to see how the performance compares
* **Using a different browser or platform**: The benchmark results may vary across different browsers or platforms, so you could test on multiple environments to get a more comprehensive understanding of the performance differences.

I hope this explanation helps!

Related benchmarks:

Object.assign vs direct assignment Mutation2 (version: 0)

Comparing performance of: Direct Assignment vs Object.assign

Created: 3 years ago by: Guest

Jump to the latest result

Direct Assignment

Object.assign

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

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