Benchmark: at vs index - MeasureThat.net

Script Preparation code:

var ARRAY_LENGTH = 1000;
var randomArray = [];
for (var i = 0; i < ARRAY_LENGTH; i++) {
    randomArray.push(Math.random())
};

Tests:

get array element using at
for(var i = 0; i<ARRAY_LENGTH; i++) { let a = randomArray.at(i); }
get array element using index
for(var i = 0; i<ARRAY_LENGTH; i++) { let a = randomArray[i]; }

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
get array element using at
get array element using index

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 10 months ago)

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/138.0.0.0 Safari/537.36

Browser/OS: Chrome 138 on Windows

View result in a separate tab

Test name	Executions per second
get array element using at	196292.8 Ops/sec
get array element using index	425745.3 Ops/sec

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

LLMs can make mistakes. Check important info.

I'd be happy to help explain the benchmark and its results.

**Benchmark Overview**

The provided JSON represents a JavaScript microbenchmark that tests two approaches to accessing an array element: using the `at()` method and using an index directly.

**Script Preparation Code**

The script preparation code generates a random array of length 1000, which is used for testing. The array contains only random numbers between 0 and 1.

**Html Preparation Code**

There is no HTML preparation code provided, so we can assume that the benchmark runs in a headless environment or uses a minimal HTML template to run the script.

**Benchmark Definitions**

The two individual test cases are defined as follows:

1. **get array element using at**

```javascript
for(var i = 0; i<ARRAY_LENGTH; i++) {
 let a = randomArray.at(i);
}
```

This code uses the `at()` method to access each element in the `randomArray` at an index specified by `i`. The `at()` method returns the value of the element at the given index, or throws an error if the index is out of bounds.

2. **get array element using index**

```javascript
for(var i = 0; i<ARRAY_LENGTH; i++) {
 let a = randomArray[i];
}
```

This code uses direct indexing to access each element in the `randomArray` at an index specified by `i`.

**Pros and Cons of Each Approach**

1. **Using `at()` method**
	* Pros:
		+ More readable and maintainable code (some argue)
		+ Less error-prone, as it throws an error if the index is out of bounds
	* Cons:
		+ May be slower due to the overhead of calling a function
2. **Using direct indexing**
	* Pros:
		+ Faster execution, as it avoids function call overhead
	* Cons:
		+ Less readable and maintainable code (some argue)
		+ More error-prone, as an out-of-bounds index will throw an error

**Library Usage**

There is no library usage in the provided benchmark.

**Special JS Feature or Syntax**

The `at()` method was introduced in ECMAScript 2019 (ES11). It allows you to access elements in arrays without having to use indexing or array methods like `forEach()`. The direct indexing approach used in the second test case is more traditional and widely supported, but may be slower.

**Other Alternatives**

If you're looking for alternative approaches to benchmarking JavaScript performance, consider:

1. **V8 Profiler**: A built-in tool in Chrome DevTools that allows you to profile and analyze the performance of your JavaScript code.
2. **Benchmark.js**: A popular library for benchmarking JavaScript performance.
3. **JSHint**: A static code analysis tool that can also be used for benchmarking.

Keep in mind that the choice of benchmarking library or approach depends on your specific use case, performance requirements, and testing goals.

Related benchmarks:

at vs index (version: 0)

Comparing performance of: get array element using at vs get array element using index

Created: 4 years ago by: Guest

Jump to the latest result

get array element using at

get array element using index

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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