Benchmark: JavaScript spread operator vs Object.assign performance with 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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Let's break down what's being tested in this JavaScript microbenchmark on MeasureThat.net.

The benchmark is comparing the performance of two approaches: using the spread operator (`...`) and `Object.assign()` to merge two objects into a new object.

**Approach 1: Using the Spread Operator**

```javascript
const firstObject = { sampleData: 'Hello world' };
const secondObject = { moreData: 'foo bar' };
const finalObject = { ...firstObject, ...secondObject };
```

The pros of this approach are:

* It's concise and readable.
* It doesn't require creating a new object using `Object.create()` or manipulating the prototype chain.

However, there are some potential drawbacks:

* It may not be supported in older browsers or environments that don't support the spread operator.
* It can lead to unexpected behavior if used with functions or other objects that have implicit `this` binding.

**Approach 2: Using Object.assign()**

```javascript
const firstObject = { sampleData: 'Hello world' };
const secondObject = { moreData: 'foo bar' };
const finalObject = Object.assign({}, firstObject, secondObject);
```

The pros of this approach are:

* It's widely supported across browsers and environments.
* It allows for fine-grained control over the resulting object's structure.

However, there are some potential drawbacks:

* It can be less concise and more verbose than the spread operator approach.
* It creates a new object using `Object.create()` or manipulating the prototype chain, which may have performance implications.

**Library Used:**

In this benchmark, neither library is explicitly used. However, it's worth noting that `Object.assign()` has been a part of the ECMAScript standard since 2015 and is widely supported across modern browsers and environments.

**Special JS Feature/Syntax:**

The spread operator (`...`) was introduced in ECMAScript 2015 (ES6) and provides a concise way to merge objects. It's also used in other features like destructuring assignment.

Overall, this benchmark aims to measure the performance difference between two common approaches to object merging in JavaScript. By comparing these approaches, we can better understand the trade-offs and potential pitfalls of each method.

Related benchmarks:

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

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

Created: 4 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):