Benchmark: slice vs at vs pop

Script Preparation code:

arr = Array.from(Array(10).keys())

Tests:

arr 0
arr[0]
arr length
arr[arr.length - 1]
at -1
arr.at(-1)
slice
arr.slice(-1)[0]

Historical Performance Data aggregated from 7 community runs

Desktop Results:

Chrome 7 runs

arr 0

154.3M/s

at -1

152.2M/s

arr length

147.9M/s

slice

49.2M/s

Fastest: arr 0 (3.1x faster)

View exact numbers

✓ arr 0: 154,286,912 ops/sec
• at -1: 152,150,176 ops/sec
• arr length: 147,884,656 ops/sec
• slice: 49,221,828 ops/sec

Results show median performance across all community submissions. Run this benchmark yourself to verify on your device.

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
arr 0
arr length
at -1
slice

Fastest: N/A

Slowest: N/A

Latest run results:

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

User agent: Mozilla/5.0 (X11; Linux x86_64; rv:140.0) Gecko/20100101 Firefox/140.0

Browser/OS: Firefox 140 on Linux

View result in a separate tab

arr length

253.9M/s

arr 0

238.8M/s

at -1

169.2M/s

slice

7.0M/s

View exact numbers

Test name	Executions per second
✓ arr length	253,929,808 Ops/sec
arr 0	238,784,928 Ops/sec
at -1	169,233,136 Ops/sec
slice	6,988,096 Ops/sec

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

LLMs can make mistakes. Check important info.

Let's break down the benchmark test case and its individual tests.

**Benchmark Test Case**

The provided JSON represents a JavaScript microbenchmark test case on MeasureThat.net. The test case is called "slice vs at vs pop" and it involves measuring the performance of three different ways to access elements in an array: using `at()`, `slice()`, and indexing (using square brackets).

**Options Compared**

Three options are compared:

1. `at()` - a method introduced in ECMAScript 2019 that allows accessing array elements by index.
2. `slice()` - a method that returns a shallow copy of a portion of an array.
3. Indexing (using square brackets) - the traditional way of accessing array elements using their index.

**Pros and Cons**

Here's a brief overview of each option:

* `at()`: This method is efficient because it uses a specialized indexing mechanism in V8, which allows for faster access to array elements. However, it requires JavaScript 2019 or later.
* `slice()`: This method creates a new array with the desired elements and returns it. While it's generally slower than using square brackets, it can be useful when you need to extract a subset of an array without modifying its original form.
* Indexing (using square brackets): This is the traditional way of accessing array elements in JavaScript. It's simple but may not be as efficient as `at()` or `slice()`, especially for large arrays.

**Library and Its Purpose**

None of these options use a library specifically. They are all built-in methods in JavaScript.

**Special JS Feature or Syntax**

The `at()` method is the only one that uses a new syntax introduced in ECMAScript 2019. This syntax allows for more expressive way of accessing array elements.

**Benchmark Preparation Code and Individual Test Cases**

The benchmark preparation code creates an array with 10 elements, and each test case targets a different element:

1. `arr[0]`: Accessing the first element of the array.
2. `arr[arr.length - 1]`: Accessing the last element of the array.
3. `arr.at(-1)`: Using the `at()` method to access the last element of the array.
4. `arr.slice(-1)[0]`: Creating a new array with the last element and extracting it.

**Other Alternatives**

If you want to measure performance in JavaScript, there are other alternatives to MeasureThat.net:

* Browser's built-in performance testing tools (e.g., Chrome DevTools)
* Node.js built-in performance testing tools
* Third-party libraries like Benchmark.js or jsperf
* Online platforms that provide similar benchmarking capabilities, such as jsPerf or JSBench

Keep in mind that each alternative may have its own strengths and weaknesses, so it's essential to choose the one that best suits your needs.

slice vs at vs pop (version: 0) Benchmark.js

Comparing performance of: `arr 0 vs arr length vs at -1 vs slice`

Created: 3 years ago by: Guest

Go to the latest result

arr 0

arr length

at -1

slice

Historical Performance Data aggregated from 7 community runs

Desktop Results:

Chrome 7 runs

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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

slice vs at vs pop (version: 0) Benchmark.js

Comparing performance of: arr 0 vs arr length vs at -1 vs slice

Created: 3 years ago by: Guest

Go to the latest result

arr 0

arr length

at -1

slice

Historical Performance Data aggregated from 7 community runs

Desktop Results:

Chrome 7 runs

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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

Related benchmarks

Comparing performance of: `arr 0 vs arr length vs at -1 vs slice`