Benchmark: JavaScript spread operator vs Object.assign performance - new object

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

Latest run results:

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

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**What is being tested?**

The provided JSON represents a JavaScript microbenchmark on the performance of two methods: using the spread operator (`...`) to create a new object by merging two existing objects, and using `Object.assign()` to achieve the same result.

**Options compared**

Two options are being compared:

1. **Using the spread operator (`...`)**: This method uses the rest-spread syntax to create a new object by spreading the properties of two existing objects into a new object.
2. **Using `Object.assign()`**: This method uses the `Object.assign()` function to merge two or more source objects into a single destination object.

**Pros and cons of each approach**

**Using the spread operator (`...`)**:

Pros:

* More concise and expressive syntax
* Can be easier to read and understand, especially for developers familiar with the syntax
* Can handle nested objects and arrays

Cons:

* May not perform as well in older browsers or those that don't support modern JavaScript features
* Can lead to slower performance due to the creation of a new object

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

Pros:

* Wide browser support, including older versions
* Can be faster for large datasets due to optimized implementations in some browsers
* More control over the merging process, as each property can be explicitly specified

Cons:

* Less concise and more verbose syntax
* May require additional configuration or libraries for nested objects and arrays

**Library usage**

There is no library mentioned in the provided JSON. However, it's worth noting that `Object.assign()` was introduced in ECMAScript 2015 (ES6), so if this benchmark were created earlier, a polyfill might be necessary for older browsers.

**Special JS feature or syntax**

The spread operator (`...`) and `Object.assign()` are both part of the modern JavaScript syntax. The spread operator was introduced in ECMAScript 2015 (ES6) as a way to create new objects from existing ones, while `Object.assign()` has been around since its introduction in ECMAScript 2009 (ECMAScript 5).

**Other alternatives**

If using either of these methods is not suitable for your use case, alternative approaches could include:

* **Lodash's `merge()` function**: A popular utility library that provides a merge function for combining objects.
* **Array.prototype.reduce() and Object.assign()**: Combining reduce with object assign can create new objects from existing ones.
* **For loops or recursive functions**: Manual looping through properties and assigning values to a new object.

Keep in mind that each of these alternatives has its own trade-offs in terms of performance, readability, and maintenance.

Related benchmarks:

JavaScript spread operator vs Object.assign performance - new object (version: 0)

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

Created: 7 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):