Benchmark: Object.assign vs object assign

Tests:

Object.assign
var params = { b:"hello", c: true, d:7 }; var other = Object.assign({ a: 2 }, params);
spread operator
var params = { b:"hello", c: true, d:7 }; var other = { a: 2, ...params };
object assign
var params = { b:"hello", c: true, d:7 }; params.a = 2; var other = params;

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Object.assign
spread operator
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/119.0.0.0 Safari/537.36

Browser/OS: Chrome 119 on Windows

View result in a separate tab

Test name	Executions per second
Object.assign	5725621.5 Ops/sec
spread operator	18785156.0 Ops/sec
object assign	1299812608.0 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 provided benchmark and explain what's being tested.

**Benchmark Definition**

The benchmark is defined in two parts:

1. **Script Preparation Code**: This section is empty, which means that the script to be executed for each test case is not provided. The script will be generated automatically by MeasureThat.net.
2. **Html Preparation Code**: This section is also empty, indicating that no HTML code is required for the benchmark.

**Individual Test Cases**

There are three individual test cases:

1. **Object.assign**
```javascript
var params = { b: "hello", c: true, d: 7 };
var other = Object.assign({ a: 2 }, params);
```
This test case creates an object `params` with properties `b`, `c`, and `d`. Then, it uses the `Object.assign()` method to create another object `other` by merging the `params` object with an initial object `{ a: 2 }`.

Pros:

* This approach is straightforward and easy to understand.
* It allows for efficient merging of objects.

Cons:

* Performance might be affected if the merged object is large.
* The `Object.assign()` method creates a new object, which can lead to memory allocation issues.

2. **Spread Operator**
```javascript
var params = { b: "hello", c: true, d: 7 };
var other = { a: 2, ...params };
```
This test case creates an object `params` with properties `b`, `c`, and `d`. Then, it uses the spread operator (`...`) to create another object `other` by copying the properties of `params` into an initial object `{ a: 2 }`.

Pros:

* The spread operator is more memory-efficient than `Object.assign()`.
* It creates a new object without the overhead of method calls.

Cons:

* This approach might be less intuitive for developers unfamiliar with the spread operator.
* Some older browsers may not support the spread operator.

3. **Object Assign (manual assignment)**
```javascript
var params = { b: "hello", c: true, d: 7 };
params.a = 2;
var other = params;
```
This test case creates an object `params` with properties `b`, `c`, and `d`. Then, it manually assigns a value to the `a` property of `params` and copies the entire `params` object into another variable `other`.

Pros:

* This approach is simple and easy to understand.
* It can be useful for developers who prefer manual assignment.

Cons:

* Performance might be slower than using `Object.assign()` or the spread operator.
* This approach involves more code duplication.

**Libraries Used**

None of the test cases explicitly use any libraries. However, if we analyze the code, we can see that `Object.assign()` is a built-in JavaScript method.

**Special JS Features/Syntax**

The spread operator (`...`) was introduced in ECMAScript 2018 (ES10). It's a new feature that allows creating objects or arrays from iterables. This feature is widely supported in modern browsers and Node.js environments.

In summary, the benchmark tests three approaches to assigning properties to an object:

1. Using `Object.assign()`
2. Using the spread operator (`...`)
3. Manual assignment

Each approach has its pros and cons, which are discussed above. The spread operator is a more memory-efficient alternative to `Object.assign()`, but it might be less intuitive for developers unfamiliar with this feature.

Related benchmarks:

Object.assign vs object assign (version: 0)

Comparing performance of: Object.assign vs spread operator vs object assign

Created: 7 years ago by: Guest

Jump to the latest result

Object.assign

spread operator

object assign

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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