Benchmark: reassign vs assign

Tests:

with re-assignment
let obj = {}; let obj2 = {one: 1, two : 2, three: 3, four : 4, five: 5 } obj = obj2;
with Object.assign
let obj = {}; let obj2 = {one: 1, two : 2, three: 3, four : 4, five: 5 } Object.assign(obj, obj2);

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
with re-assignment
with Object.assign

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 2 years ago)

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/104.0.0.0 Safari/537.36

Browser/OS: Chrome 104 on Windows

View result in a separate tab

Test name	Executions per second
with re-assignment	678856704.0 Ops/sec
with Object.assign	2690788.0 Ops/sec

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

LLMs can make mistakes. Check important info.

Let's dive into the explanation of what's tested in this benchmark.

**Benchmark Overview**

This benchmark compares two approaches for reassigning an object: using the assignment operator (`=`) and using the `Object.assign()` method.

**Approach 1: Reassignment with Assignment Operator (`=`)**

In this approach, the test code uses the assignment operator to reassign the value of a variable. Specifically, it creates a new object `obj2` with several properties and then assigns its value to the variable `obj`. The goal is to measure how fast the JavaScript engine can perform this assignment operation.

**Approach 2: Reassignment using Object.assign()**

In this approach, the test code uses the `Object.assign()` method to reassign the value of a variable. It creates a new object `obj2` with several properties and then calls `Object.assign()` on the `obj` variable, passing `obj2` as an argument. The goal is to measure how fast the JavaScript engine can perform this assignment operation.

**Pros and Cons**

* **Assignment Operator (`=`)**:
	+ Pros: Simple and straightforward.
	+ Cons: May not be optimized for performance due to its simplicity.
* **Object.assign()**:
	+ Pros: Can handle more complex assignment scenarios, such as merging multiple objects.
	+ Cons: May introduce overhead due to the method call and object creation.

**Other Considerations**

* Both approaches create a new object on the heap, which can lead to garbage collection overhead.
* The `Object.assign()` method may also perform additional checks, such as ensuring that the target variable is an object, which could introduce additional overhead.

**Library and Special JS Features**

There are no libraries used in this benchmark. Additionally, there are no special JavaScript features or syntax mentioned in the benchmark definition or test cases.

**Alternative Approaches**

Other possible approaches for reassigning an object could include:

* Using a library like Lodash's `merge()` function
* Using a custom implementation of assignment, such as using a closure or a function constructor
* Using a different data structure, such as a typed array or a buffer

However, these alternatives are not explored in this benchmark.

**Benchmark Preparation Code**

The script preparation code is empty, which means that the test code starts with a clean slate and does not include any additional setup or cleanup. The HTML preparation code is also empty, which suggests that no HTML-related setup or teardown is required for the test.

Related benchmarks:

reassign vs assign (version: 0)

Comparing performance of: with re-assignment vs with Object.assign

Created: 2 years ago by: Guest

Jump to the latest result

with re-assignment

with Object.assign

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

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