Benchmark: JavaScript spread operator vs Object.assign performance 2000

Tests:

Using the spread operator
const searchParams = {}; const email = "email" // const email = getCookie("email"); const firstname = "firstname" // const firstname = getCookie("firstname"); const lastname = "lastname" // const lastname = getCookie("lastname"); const phone = "phone" // const phone = getCookie("phone"); // const cookieValues = { // email, // firstname, // lastname, // phone, // }; let cookieValues = {} if (email) { cookieValues.email = email} if (firstname) { cookieValues.firstname = firstname} if (lastname) { cookieValues.lastname = lastname} if (phone) { cookieValues.phone = phone} Object.assign(searchParams, cookieValues);
Using Object.assign
const searchParams = {}; const email = "email"; const firstname = "firstname"; const lastname = "lastname"; const phone = "phone"; Object.assign(searchParams, { email, firstname, lastname, phone, });

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Using the spread operator
Using Object.assign

Fastest: N/A

Slowest: N/A

Latest run results:

No previous run results

This benchmark does not have any results yet. Be the first one to run it!

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

LLMs can make mistakes. Check important info.

Let's break down what's being tested in this benchmark.

**Benchmark Definition**

The benchmark is comparing two approaches for assigning properties to an object: using the spread operator (`...`) and `Object.assign()`. The benchmark definition provides a sample script that initializes several variables, including `email`, `firstname`, `lastname`, and `phone`. These values are stored in an object called `cookieValues`.

**Test Case 1: Using the spread operator**

The first test case uses the spread operator to assign properties from `cookieValues` to the `searchParams` object. The syntax is:
```javascript
Object.assign(searchParams, cookieValues);
```
This creates a shallow copy of `cookieValues` and merges it with `searchParams`.

**Test Case 2: Using Object.assign**

The second test case uses `Object.assign()` to assign properties from `cookieValues` to the `searchParams` object. The syntax is:
```javascript
Object.assign(searchParams, { email, firstname, lastname, phone });
```
This creates a shallow copy of an object with only the `email`, `firstname`, `lastname`, and `phone` properties.

**Options Compared**

The two options being compared are:

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

**Pros and Cons of Each Approach**

**Using the Spread Operator:**

Pros:

* Concise syntax
* Can be more readable for simple assignments

Cons:

* Can be slower due to the overhead of creating a new object
* Limited support in older browsers (pre-ES6)

**Using Object.assign():**

Pros:

* Well-supported across most modern browsers
* Can be faster due to optimized implementation
* More flexible, as it can handle merging objects with arrays and null values

Cons:

* Less concise syntax
* May require more code for complex assignments

**Other Considerations**

* Both approaches create a shallow copy of the source object. If you need to merge objects deeply, using `Object.assign()` might be a better choice.
* The spread operator is a part of ES6+ syntax, so if you need to support older browsers, `Object.assign()` might be a better option.

**Library and Special JS Feature/Syntax**

There are no specific libraries mentioned in the benchmark definition. However, it's worth noting that some implementations of `Object.assign()` may use polyfills or workarounds for older browsers.

The spread operator is a new JavaScript syntax introduced in ES6+. It allows you to create new objects by spreading the properties of an existing object.

**Alternatives**

Some alternative approaches to comparing performance might include:

* Using a simple loop to iterate over the properties and assign them individually
* Using `Object.create()` or other methods for creating new objects
* Using `Array.prototype.slice()` or other methods for creating shallow copies

Related benchmarks:

JavaScript spread operator vs Object.assign performance 2000 (version: 0)

Comparing performance of: Using the spread operator vs Using Object.assign

Created: 3 years ago by: Guest

Jump to the latest result

Using the spread operator

Using Object.assign

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

No previous run results

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