Benchmark: Spread vs pusha - MeasureThat.net

Tests:

test1
a=[1,2,3,4,1,2,3]; b = [...new Set([...a])]
test2
a=[1,2,3,4,1,2,3]; b=[]; b.push(...new Set([...a]));

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
test1
test2

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 3 years ago)

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/90.0.4430.212 Safari/537.36

Browser/OS: Chrome 90 on Windows

View result in a separate tab

Test name	Executions per second
test1	915514.4 Ops/sec
test2	618743.1 Ops/sec

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

LLMs can make mistakes. Check important info.

I'll break down the provided benchmark and explain what's being tested, compared options, pros and cons of those approaches, and other considerations.

**Benchmark Overview**

The benchmark measures the performance difference between two JavaScript approaches: using `Array.prototype.push()` with spreading the array elements, and using `Set` objects with the spread operator (`...`). The benchmark uses a simple test case: creating an array from 1 to 6, then creating a new set from that array, and finally pushing all unique elements of the original array onto another empty array.

**Options Compared**

The two options being compared are:

1. `a = [...new Set([...a])]`: This approach uses the spread operator (`...`) to create a new set from the array elements, and then uses the spread operator again to push all unique elements of the original array onto an empty array.
2. `b = []; b.push(...new Set([...a]))`: This approach creates a new empty array `b` and then pushes all unique elements of the original array onto it using the spread operator.

**Pros and Cons**

### Option 1: Using `Array.prototype.push()` with Spreading

Pros:

* Faster execution time, since `push()` is a built-in method optimized for performance.
* More intuitive code, as it directly modifies the original array.

Cons:

* May lead to incorrect results if the array's length is not preserved, which can happen when using `set()`.
* Can be less efficient if the array contains many duplicate elements, since `push()` will only add new elements, and some duplicates will be ignored.

### Option 2: Using `Set` Objects with the Spread Operator

Pros:

* More predictable results, as sets ensure uniqueness of elements.
* Can handle large arrays with many duplicate elements efficiently, since sets only store unique values.

Cons:

* Slower execution time, since creating a set and using its spread operator may introduce additional overhead.
* Less intuitive code, as it requires understanding the behavior of sets and their spread operator.

**Library Usage**

In this benchmark, no libraries are explicitly used. However, `Array.prototype.push()` is a built-in method, while `Set` objects are part of the ECMAScript standard.

**Special JS Features/Syntax**

This benchmark uses the following special JavaScript features:

* The spread operator (`...`) in both options.
* Using template literals (`\r\n`) to separate lines in the test case code.
* The use of `new Set()` and its spread operator to create a set from an array.

**Other Considerations**

When choosing between these two approaches, consider the trade-offs between execution time, predictability, and code readability. If performance is critical and the input data does not contain many duplicates, Option 1 might be preferred. However, if uniqueness of elements is crucial or the input data is large with many duplicate values, Option 2 is likely a better choice.

**Alternatives**

Other alternatives for this benchmark could include:

* Using `JSON.parse(JSON.stringify(a))` to create an array copy and then pushing its unique elements onto another array.
* Using `Array.from()` and `Set.prototype.values()` to create a new set from the array and push its unique elements onto another array.
* Using a library like Lodash's `uniqBy()` function to remove duplicates from the array before pushing it onto another array.

Keep in mind that these alternatives may have different trade-offs in terms of execution time, code readability, and maintenance complexity.

Related benchmarks:

Spread vs pusha (version: 0)

testaa

Comparing performance of: test1 vs test2

Created: 3 years ago by: Guest

Jump to the latest result

test1

test2

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

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