Benchmark: Map benchmark - MeasureThat.net

Script Preparation code:

var map = new Map()
var obj = {}

for (let i = 0; i++; i < 100_000) {
    map.set(`${i}`, 42)
    obj[`${i}`] = 42
}

Tests:

Map lookup
for (let i = 10_000; i < 60_000; i++) { map.get(`${i}`) }
Obj lookup
for (let i = 10_000; i < 60_000; i++) { map.get(`${i}`) }

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Map lookup
Obj lookup

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 provided benchmark and explain what is tested, compared, and their pros/cons.

**Benchmark Definition**

The benchmark definition represents a JavaScript microbenchmark that compares the performance of two data structures: `Map` and plain objects (`obj`). The script preparation code creates an empty map and object, then populates them with 100,000 key-value pairs. The Html preparation code is null, indicating that no HTML page is used for this benchmark.

**Script Preparation Code**

```javascript
var map = new Map();
var obj = {};

for (let i = 0; i++; i < 100_000) {
    map.set(`${i}`, 42);
    obj[`${i}`] = 42;
}
```

This code creates an empty `Map` and object, then iterates over a range of numbers from 0 to 99,999 (inclusive), setting each number as both a key in the map and an index in the object. The value associated with each key is always "42".

**Html Preparation Code**

Since it's null, there's no HTML preparation code.

**Individual Test Cases**

There are two test cases:

1. **Map lookup**
```javascript
for (let i = 10_000; i < 60_000; i++) {
    map.get(`${i}`);
}
```
This test case iterates over a range of numbers from 10,000 to 59,999 and repeatedly calls the `get` method on the map with each key.

2. **Obj lookup**
```javascript
for (let i = 10_000; i < 60_000; i++) {
    obj[`${i}`];
}
```
This test case is identical to the previous one, but instead of calling `map.get`, it calls the bracket notation (`obj[key]`) on the object.

**Comparison**

The two test cases compare the performance of map lookups and object lookups. The comparison aims to determine which approach is faster in terms of execution speed.

**Pros/Cons**

Here are some pros and cons for each approach:

* **Map lookup**
	+ Pros:
		- Efficient use of JavaScript engines' built-in `get` method.
		- Can take advantage of modern JavaScript engine optimizations (e.g., caching).
	+ Cons:
		- May require more memory to store the map, especially for large datasets.
		- Map lookups might not be as cache-friendly as object lookups in some cases.
* **Obj lookup**
	+ Pros:
		- Typically faster than map lookups due to less overhead and better caching.
		- Can be more memory-efficient, as objects don't require storing keys.
	+ Cons:
		- May require manual index management (e.g., incrementing indices).
		- Bracket notation can be slower for large datasets or nested objects.

**Library**

In this benchmark, the `Map` object is used. The `Map` API is a built-in JavaScript object that provides a way to store key-value pairs in an ordered sequence. It's similar to a dictionary or hash table and is optimized for fast lookups.

**Other Alternatives**

If you wanted to compare other data structures for this benchmark, here are some alternatives:

* **Array**: You could use arrays instead of maps or objects by iterating over the array and accessing elements using numerical indices.
* **Set**: If you want to focus on hash-based data structures, you could replace maps with `Set` objects.
* **WeakMap**: For a more memory-efficient approach, you could use `WeakMap`, which is similar to `Map` but doesn't store keys in memory.

Keep in mind that each alternative may change the benchmark's characteristics and might not be suitable for all scenarios.

Latest run results:

Run details: (Test run date: 2 years ago)

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/103.0.5060.114 Safari/537.36 Edg/103.0.1264.62

Browser/OS: Chrome 103 on Windows

View result in a separate tab

Test name	Executions per second
Map lookup	289.8 Ops/sec
Obj lookup	254.3 Ops/sec

Related benchmarks:

Map benchmark (version: 0)

Lookup of map vs object

Comparing performance of: Map lookup vs Obj lookup

Created: 2 years ago by: Guest

Jump to the latest result

Map lookup

Obj lookup

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):