Benchmark: JS spread operator vs Object.assign performance

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 the provided benchmark and explain what is being tested.

**Benchmark Purpose:**
The main purpose of this benchmark is to compare the performance of two methods for merging objects in JavaScript:

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

**Options Compared:**

* The spread operator (`...`) is used to create a new object by copying all enumerable properties from one or more source objects.
* `Object.assign()` is a method that copies all enumerable own properties from one or more source objects to a target object.

**Pros and Cons of Each Approach:**

* **Spread Operator (using the spread operator):**
	+ Pros:
		- More readable and concise code
		- Does not create an intermediate object, which can reduce memory usage
	+ Cons:
		- May be slower due to the creation of a new object
		- Can lead to shallow copying issues if one object contains other objects that are also being merged
* **Object.assign():**
	+ Pros:
		- Faster and more efficient than creating a new object with the spread operator
		- Allows for deeper copying by using an options object with `deep` set to true
	+ Cons:
		- Less readable and more verbose code
		- Creates an intermediate object, which can increase memory usage

**Library Used:**
None. This benchmark only uses built-in JavaScript features.

**Special JS Feature or Syntax:**
The spread operator (`...`) was introduced in ECMAScript 2018 (ES9) as a new syntax for creating objects.

**Other Considerations:**

* The benchmark measures the time it takes to execute each test case, which can be affected by various factors such as CPU speed, memory availability, and browser version.
* To get accurate results, ensure that the testing environment is consistent across all runs.

**Alternative Benchmarks:**
There are other benchmarks available for comparing object merging methods in JavaScript. Some examples include:

* Benchmarking libraries like Benchmark.js or js-benchmark
* Online platforms like JSFiddle or CodePen, which offer built-in benchmarking tools

When creating your own benchmark, consider the following best practices:

1. Use a consistent testing environment to ensure reproducible results.
2. Choose relevant test cases that cover different scenarios and edge cases.
3. Measure execution time accurately using a reliable timer library.
4. Keep the benchmark code concise and readable.
5. Consider adding additional metrics, such as memory usage or CPU utilization, for a more comprehensive picture of performance.

Related benchmarks:

JS spread operator vs Object.assign performance (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):