Benchmark: JavaScript spread operator vs Object.assign performance with new object in assign and helper function - sorry didnt validate

Script Preparation code:

window.merge = (o1, o2) => Object.assign({}, o1, o2);

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 = window.merge(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 dive into the world of JavaScript microbenchmarks!

**Benchmark Overview**

The provided benchmark, hosted on MeasureThat.net, compares the performance of two approaches for creating a new object by combining two existing objects: using the spread operator (`...`) and `Object.assign()`. The test is designed to measure which method is faster.

**Test Options Compared**

There are two test cases:

1. **Using the Spread Operator**: This approach uses the spread operator (`...`) to create a new object by spreading the properties of two existing objects, `firstObject` and `secondObject`, into a new object.
2. **Using Object.assign()**: This approach uses the `Object.assign()` method to merge two existing objects, `firstObject` and `secondObject`, into a new object.

**Pros and Cons of Each Approach**

1. **Using the Spread Operator**
	* Pros:
		+ Concise and readable syntax.
		+ Works with most modern browsers and Node.js versions.
	* Cons:
		+ Can be slower than `Object.assign()` due to additional overhead for parsing and executing the spread operator.
2. **Using Object.assign()**
	* Pros:
		+ Generally faster than the spread operator, especially in older browsers and Node.js versions.
		+ More control over the merging process, as it allows specifying an optional third argument (the target object).
	* Cons:
		+ Less concise syntax compared to the spread operator.
		+ May not work with all types of objects or arrays.

**Library Used**

The `window.merge` function is a custom implementation of `Object.assign()` for this benchmark. It's used as a helper function to perform the merge operation in both test cases.

**Special JS Features/Syntax**

The spread operator (`...`) is a feature introduced in ECMAScript 2015 (ES6). It allows creating new objects by spreading the properties of existing objects into a new object.

**Benchmark Preparation Code Explanation**

The `window.merge` function is defined as an alias for `Object.assign()`, which means it's simply a reassignment of the `merge` property to point to the `assign` method on the global `Object` object. This allows the benchmark to use a custom implementation of `Object.assign()`.

**Other Alternatives**

If you need to create a new object by combining two existing objects, there are other alternatives:

* Using the `Array.prototype.concat()` method: `const finalObject = Array.prototype.concat([firstObject, secondObject])[0];`
* Using a library like Lodash's `merge()` function: `const finalObject = _merge(firstObject, secondObject);`

However, these alternatives may not be as concise or readable as the spread operator or `Object.assign()`.

Related benchmarks:

JavaScript spread operator vs Object.assign performance with new object in assign and helper function - sorry didnt validate (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):