Benchmark: JS Array[] vs Map.get()

Script Preparation code:

var arr = new Array(2000);
var ms = new Map();
var i = 0;

while (i <= 2000) {
  arr[i] = i;
  ms.set(i, i);
  i++;
}

Tests:

Array[]
const index = arr[1999];
Map.get
ms.get(1999)

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Array[]
Map.get

Fastest: N/A

Slowest: N/A

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

LLMs can make mistakes. Check important info.

Let's break down the benchmark and explain what's being tested, compared, and considered.

**Benchmark Definition**

The benchmark compares two approaches for accessing an element in an array: using `Array[]` (traditional indexing) versus using a `Map`'s `get()` method. The script prepares two data structures:

1. An empty array `arr` with 2000 elements.
2. A new instance of the `Map` interface `ms`, which is initialized as an empty map.

The script then iterates from 0 to 1999, setting each element in the array and corresponding value in the map using the `set()` method.

**Options Compared**

Two options are being compared:

1. **Array[]**: Traditional indexing of the array.
2. **Map.get()**: Using a `Map` to store key-value pairs and retrieving values using the `get()` method.

**Pros and Cons**

Here's a brief overview of each approach:

* **Array[]**:
	+ Pros: Simple, widely supported, and efficient for small datasets.
	+ Cons: Can be slow for large datasets due to bounds checking and indexing overhead.
* **Map.get()**:
	+ Pros: Efficient for large datasets since maps use hash-based lookup. Also, maps can handle concurrent updates and are more memory-efficient than arrays for storing large amounts of data.
	+ Cons: Requires additional memory allocation and creation of a map object, which may have initialization overhead.

**Library and Purpose**

The `Map` interface is a built-in JavaScript API that provides a way to store key-value pairs. The purpose of using a `Map` in this benchmark is to demonstrate the efficiency of map-based lookups for accessing elements in a dataset. The `get()` method is used to retrieve values from the map by providing the corresponding key.

**Special JS Feature or Syntax**

The `set()` and `map` functions are part of the ECMAScript 2015 (ES6) standard, introduced in JavaScript engines like V8 for Google Chrome. This means that this benchmark requires a recent version of Chrome (or other compatible browser) to run.

**Other Alternatives**

If you wanted to test alternative approaches, some possible alternatives could include:

* **Using `Object.keys()` and array indexing**: This approach uses the `Object.keys()` method to get an array-like object containing the keys of the map, which can be used for indexing.
* **Using a custom data structure (e.g., `Set` or `WeakMap`)**: Depending on the specific requirements, you could experiment with other data structures that offer efficient lookups and storage.

Keep in mind that these alternatives may have different performance characteristics or trade-offs compared to the original benchmark.

Latest run results:

Run details: (Test run date: 5 months ago)

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/125.0.0.0 Safari/537.36

Browser/OS: Chrome 125 on Mac OS X 10.15.7

View result in a separate tab

Test name	Executions per second
Array[]	28983980.0 Ops/sec
Map.get	28519134.0 Ops/sec

Related benchmarks:

JS Array[] vs Map.get() (version: 0)

Compare Array[] vs Map.get() for a small amount of data

Comparing performance of: Array[] vs Map.get

Created: 5 months ago by: Guest

Jump to the latest result

Array[]

Map.get

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

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