Benchmark: JavaScript spread operator vs Object.assign performanc

Tests:

Using the spread operator
const firstObject = { sampleData: 'Hello world' } const secondObject = { moreData: 'foo bar' } const finalObject = { ...firstObject, ...secondObject };
Using Object.assign
const firstObject = { sampleData: 'Hello world' } const secondObject = { moreData: 'foo bar' } const finalObject = Object.assign({}, firstObject, secondObject);

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

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

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

**Benchmark Definition**

The benchmark is designed to compare the performance of two approaches: using the JavaScript spread operator (`...`) and `Object.assign()` to merge two objects.

**Options Compared**

There are two options being compared:

1. **Using the Spread Operator (`...`)**: This method uses the spread operator to create a new object that includes all the properties from both `firstObject` and `secondObject`.
2. **Using `Object.assign()`**: This method uses the `Object.assign()` method to create a new object that includes all the properties from both `firstObject` and `secondObject`.

**Pros and Cons of Each Approach**

**Using the Spread Operator (`...`)**

Pros:

* More concise and readable code
* Can be used with any type of object, not just objects with enumerable properties
* Can be chained together to create more complex merges

Cons:

* May incur a performance overhead due to the creation of a new object
* Can lead to unexpected behavior if not used carefully (e.g., when merging arrays)

**Using `Object.assign()`**

Pros:

* Fast and efficient, as it uses a native method
* Can be used with any type of object, including arrays

Cons:

* Less readable and concise code compared to the spread operator
* May require more boilerplate code (e.g., creating an empty object to merge into)

**Other Considerations**

In terms of performance, both approaches are generally fast and efficient. However, the `Object.assign()` method may have a slight edge due to its native implementation.

When it comes to readability, the spread operator is often preferred due to its concise and expressive syntax.

If you're working with objects that have nested properties or arrays, the spread operator can be a convenient choice. However, if you need to merge complex data structures, `Object.assign()` may be a better option.

**Library Used**

In this benchmark, neither library is explicitly used. However, `Object.assign()` is a built-in JavaScript method that is widely supported by most modern browsers and Node.js environments.

**Special JS Feature/Syntax**

The benchmark uses the spread operator (`...`), which is a relatively new feature in JavaScript introduced in ECMAScript 2018 (ES10). The syntax allows you to create a new object with all the properties from an existing object, making it a concise way to merge objects.

If you're not familiar with the spread operator, think of it as a shorthand for `Object.assign()` or other methods that achieve similar results.

**Alternatives**

Some alternative approaches to merging objects in JavaScript include:

* Using `lodash` library's `merge()` function
* Using `immer` library's `from` function
* Creating a new object using the dot notation (e.g., `finalObject.sampleData = firstObject.sampleData; finalObject.moreData = secondObject.moreData;`)
* Using other built-in methods like `JSON.parse(JSON.stringify(firstObject, secondObject))`

However, these alternatives may not be as concise or efficient as the spread operator or `Object.assign()` in this specific benchmark.

Related benchmarks:

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

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

Created: 6 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):