Benchmark: array[array.length - 1] vs array.at(-1) 4

Script Preparation code:

var array = [1,2,3,2,3,2,3,2,3,2,3,2,3,2,3,2,3,2,3,2,3,2,3,2,3,2,3,2,3,2,3,2,3];

Tests:

array.at(-1)
return array.at(-1);
array[array.length - 1]
return array[array.length - 1];

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
array.at(-1)
array[array.length - 1]

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: one year ago)

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/112.0.0.0 Safari/537.36 Edg/112.0.1722.39

Browser/OS: Chrome 112 on Windows

View result in a separate tab

Test name	Executions per second
array.at(-1)	4370092.5 Ops/sec
array[array.length - 1]	2273550.0 Ops/sec

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

LLMs can make mistakes. Check important info.

**Overview of the Benchmark**

The provided JSON represents a JavaScript microbenchmark test case on MeasureThat.net. The benchmark compares the performance of two approaches: `array.at(-1)` and `array[array.length - 1]`. This test measures how fast each approach can retrieve the last element of an array.

**Options Compared**

Two options are compared:

1. `array.at(-1)`
2. `array[array.length - 1]`

Both methods aim to access the last element of an array, but they differ in their implementation.

**Pros and Cons of Each Approach**

### Array.at(-1)

* **Pros:**
	+ More concise and readable syntax.
	+ Works with sparse arrays (arrays that contain gaps).
	+ Faster performance due to its optimized internal implementation.
* **Cons:**
	+ Not supported in older browsers (before Chrome 80).

### Array[array.length - 1]

* **Pros:**
	+ Supported in all browsers, including older ones.
	+ Works with non-sparse arrays without requiring additional setup.
* **Cons:**
	+ Less concise and readable syntax.
	+ Might be slower than `array.at(-1)` due to the need for array indexing.

**Library Used (if applicable)**

None. Both approaches rely on standard JavaScript features.

**Special JS Features or Syntax**

No special features or syntax are used in this benchmark.

**Other Considerations**

When choosing between `array.at(-1)` and `array[array.length - 1]`, consider the following:

* If you need to support older browsers, use `array[array.length - 1]`.
* If you prioritize performance and concise code, use `array.at(-1)`.
* Be aware that `array.at(-1)` might not work with sparse arrays if they contain gaps.

**Alternatives**

If you're interested in exploring other JavaScript microbenchmarks or comparing different array methods, consider the following alternatives:

1. MeasureThat.net offers a range of benchmarks, including comparisons between other JavaScript methods like `map()`, `filter()`, and `reduce()`.
2. You can use other online benchmarking tools, such as JSDoc's Benchmarker or JSPerf.
3. For more complex scenarios, consider using a test framework like Jest or Mocha to write and run your own benchmarks.

Keep in mind that the best approach depends on your specific use case and performance requirements.

Related benchmarks:

array[array.length - 1] vs array.at(-1) 4 (version: 0)

Comparing performance of: array.at(-1) vs array[array.length - 1]

Created: one year ago by: Guest

Jump to the latest result

array.at(-1)

array[array.length - 1]

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):