Benchmark: Spread vs Push2 - MeasureThat.net

Tests:

Spread Operator
let arr1 = Array.from({length:100000}).map((_,i)=>i); let arr2 = Array.from({length:100000}).map((_,i)=>i); arr1 = [...arr1,...arr2]
Push with Spread
let arr1 = Array.from({length:100000}).map((_,i)=>i); let arr2 = Array.from({length:100000}).map((_,i)=>i); arr2.forEach(e=>{arr1.push(e)})

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Spread Operator
Push with Spread

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 2 years ago)

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/124.0.0.0 Safari/537.36 Edg/124.0.0.0

Browser/OS: Chrome 124 on Windows

View result in a separate tab

Test name	Executions per second
Spread Operator	45.7 Ops/sec
Push with Spread	45.0 Ops/sec

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

LLMs can make mistakes. Check important info.

Let's dive into the world of JavaScript microbenchmarks on MeasureThat.net.

**Benchmark Overview**

The provided benchmark measures the performance difference between two approaches: using the spread operator (`...`) and the `push` method with spreading an array, when concatenating two arrays. The benchmark consists of two test cases:

1. **Spread Operator**: Creates two arrays of 100,000 elements each, maps them to generate new elements, and then uses the spread operator to concatenate the two arrays.
2. **Push with Spread**: Creates two arrays of 100,000 elements each, maps them to generate new elements, and then uses a `forEach` loop to push the elements from one array into another.

**Options Compared**

The benchmark compares the performance of:

1. **Spread Operator (`...`)**: Concatenates two arrays using the spread operator.
2. **Push with Spread**: Concatenates two arrays by pushing elements from one array into another using `push`.

**Pros and Cons of Each Approach**

* **Spread Operator (`...`)**:
	+ Pros:
		- Concise and readable syntax
		- Creates a new array, which can be more efficient for large datasets
		- Supports multiple source arrays for concatenation
	+ Cons:
		- Can create intermediate copies of the original arrays, leading to increased memory usage.
		- May not be as efficient as other methods for very large datasets.
* **Push with Spread**:
	+ Pros:
		- Can avoid creating intermediate copies of the original arrays.
		- More control over the concatenation process (e.g., using `splice` or `concat` instead).
	+ Cons:
		- Less readable syntax compared to the spread operator.
		- Requires more explicit looping and array manipulation.

**Library Usage**

There is no library usage mentioned in the benchmark definition. However, if a library were used, it might be something like Lodash's `concat` function or another utility library that provides an efficient way to concatenate arrays.

**Special JS Features or Syntax**

None are explicitly mentioned in this benchmark.

**Other Considerations**

When choosing between these two approaches, consider the following:

* Memory usage: If memory efficiency is critical, the spread operator might be a better choice due to its ability to create a new array.
* Readability and maintainability: For smaller datasets or simple concatenation tasks, the push method with spreading might be more readable. However, for larger datasets or complex concatenation scenarios, the spread operator's concise syntax can make code easier to understand.

**Alternatives**

If you need to concatenate arrays in JavaScript, some alternative approaches include:

* Using `concat` (native method): `arr1.concat(arr2)`
* Using `splice` with `push`: `arr1.splice(0, 0, ...arr2)`, then `arr1.push(...arr1)`
* Using a custom loop or recursion
* Using a library like Lodash's `concat`

Keep in mind that the performance differences between these methods might be negligible for small datasets, but can become significant with very large arrays.

Related benchmarks:

Spread vs Push2 (version: 0)

Comparing performance of: Spread Operator vs Push with Spread

Created: 2 years ago by: Guest

Jump to the latest result

Spread Operator

Push with Spread

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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