Benchmark: Map vs Array vs Object set uint32 key speed2

Script Preparation code:

function randomU32() {
	return Math.random() * (1 << 31) >>> 0;
}

Tests:

Map
const map = new Map() map.set(randomU32(), true);
Array
const arr = [] arr[randomU32()] = true;
Object
const obj = {} obj[randomU32()] = true;

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Map
Array
Object

Fastest: N/A

Slowest: N/A

Latest run results:

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

LLMs can make mistakes. Check important info.

I'll break down the provided benchmark and its test cases to explain what's being tested, compared, and their pros and cons.

**Benchmark Overview**

The provided JSON represents a JavaScript microbenchmark that compares the performance of three data structures: Maps, Arrays, and Objects. The goal is to measure which data structure is the fastest for setting a uint32 key with a boolean value.

**Test Cases**

There are three test cases:

1. **Map**: `const map = new Map()\r\nmap.set(randomU32(), true);`
2. **Array**: `const arr = []\r\narr[randomU32()] = true;`
3. **Object**: `const obj = {}\r\nobj[randomU32()] = true;`

**Library and Purpose**

None of the test cases use a specific library.

**Special JS Feature/Syntax**

There is no special JavaScript feature or syntax used in these test cases.

**Comparison of Data Structures**

The main difference between the three data structures lies in how they store and retrieve key-value pairs:

* **Map**: Maps are designed to store key-value pairs with fast lookups. In this benchmark, the `set` method is used to insert a key-value pair into the map.
* **Array**: Arrays use numerical indices to access elements. The expression `arr[randomU32()] = true;` sets a value at an index that's generated randomly using `Math.random() * (1 << 31) >>> 0`.
* **Object**: Objects are designed to store key-value pairs with slow lookups compared to Maps. The expression `obj[randomU32()] = true;` creates a property on an object with a dynamic name.

**Performance Comparison**

The benchmark measures the number of executions per second for each data structure. In this case, the results show:

* Map: 499,341 executions per second
* Object: 184,101 executions per second (approximately 37% slower than Map)
* Array: 199,600 executions per second (approximately 40% slower than Map)

**Pros and Cons of Each Approach**

Here's a brief summary:

* **Map**: Fast lookups make it suitable for this benchmark. However, it may have higher memory overhead due to the `Map` object.
* **Array**: While arrays are efficient in terms of memory usage, they require calculating an index using `Math.random()` which can be slower than direct lookup in a Map or Object.
* **Object**: Slow lookups make objects less suitable for this benchmark. However, they provide flexibility and ease of use when working with dynamic data.

**Other Alternatives**

If you're looking to measure the performance of other data structures, consider:

* **Set**: Similar to Maps, but without the key-value pair concept.
* **WeakMap**, **WeakSet**: Variants of Map and Set that can help with memory management in JavaScript applications.
* **IndexedDB** or **LocalStorage**: Storage solutions for client-side data storage.

Keep in mind that performance results may vary depending on the specific use case, implementation, and browser/OS version.

Related benchmarks:

Map vs Array vs Object set uint32 key speed2 (version: 0)

Comparing performance of: Map vs Array vs Object

Created: 4 years ago by: Guest

Jump to the latest result

Map

Array

Object

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

No previous run results

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