Benchmark: string[index.length -1] vs slice(-1)

Script Preparation code:

var example = 'there is no spoon'

Tests:

slice
var result = example.slice(-1)
index length
var result = example[example.length - 1]

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
slice
index length

Fastest: N/A

Slowest: N/A

Latest run results:

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

User agent: Mozilla/5.0 (Linux; Android 10; K) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/127.0.0.0 Mobile Safari/537.36

Browser/OS: Chrome Mobile 127 on Android

View result in a separate tab

Test name	Executions per second
slice	5103119.0 Ops/sec
index length	2873176.2 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 and its components.

**Benchmark Definition:**

The benchmark compares two approaches to access the last character of a string:

1. `string[index.length - 1]`: This approach uses direct indexing, where you access the string using an integer index that is one less than the length of the string.
2. `slice(-1)`: This approach uses the `slice` method, which returns a new string containing only the last character of the original string.

**Options being compared:**

The two options are being compared to see which one performs better in terms of execution time.

**Pros and Cons of each approach:**

1. **Direct indexing (`string[index.length - 1]`)**:
	* Pros:
		+ Can be more efficient since it doesn't create a new string object.
		+ Can be more cache-friendly since the index is known at compile-time.
	* Cons:
		+ May require more memory accesses or computations to calculate the length of the string.
2. **`slice(-1)`**:
	* Pros:
		+ Creates a new string object, which can be faster for some use cases (e.g., when using `concat()`).
		+ Can be simpler to understand and write.
	* Cons:
		+ Creates an unnecessary string object, which can lead to memory allocations and deallocations.
		+ May not be as cache-friendly since the slice operation is dynamic.

**Library and syntax considerations:**

In this benchmark, no specific JavaScript library or syntax feature is being used. However, it's worth noting that `slice()` is a built-in method in JavaScript, which means it's part of the ECMAScript standard.

**Special JS features or syntax:**

There are no special JavaScript features or syntaxes being used in this benchmark. The code is straightforward and doesn't employ any advanced features like async/await, promises, or decorators.

**Other alternatives:**

In this specific case, there isn't a significant alternative to the two options being compared. However, if we were to consider other approaches:

* Using `charAt()` instead of direct indexing could be an alternative.
* Using `substring(0, 1)` or `substr(0, 1)` could also be alternatives.

It's worth noting that these alternative approaches would likely have similar performance characteristics to the two options being compared, but might differ in terms of simplicity, readability, and use cases.

Related benchmarks:

string[index.length -1] vs slice(-1) (version: 0)

Compares direct index with index.length -1 vs slice

Comparing performance of: slice vs index length

Created: 2 years ago by: Guest

Jump to the latest result

slice

index length

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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