Benchmark: Map has vs array some in loop

Tests:

Array some
const referenceArray = [ {id:1},{id:2},{id:3},{id:4},{id:5},{id:6},{id:7},{id:8},{id:9},{id:0} ]; const inputArray = [ {id:5},{id:1},{id:10},{id:9},{id:5},{id:2},{id:17},{id:0},{id:4},{id:0} ]; inputArray.map(inp => ({...inp, isExisting: referenceArray.some(refA => refA.id === inp.id)}));
Map has
const referenceArray = [ {id:1},{id:2},{id:3},{id:4},{id:5},{id:6},{id:7},{id:8},{id:9},{id:0} ]; const inputArray = [ {id:5},{id:1},{id:10},{id:9},{id:5},{id:2},{id:17},{id:0},{id:4},{id:0} ]; const x = referenceArray.reduce((mapI, inp) => mapI.set(inp.id,inp), new Map()); inputArray.map(inp => ({...inp, isExisting: x.has(inp.id)}));

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Array some
Map has

Fastest: N/A

Slowest: N/A

Latest run results:

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

User agent: Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/136.0.0.0 Safari/537.36

Browser/OS: Chrome 136 on Linux

View result in a separate tab

Test name	Executions per second
Array some	5902883.5 Ops/sec
Map has	2621569.0 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 provided benchmark and its test cases.

**Benchmark Definition JSON**

The benchmark definition is quite straightforward, which represents two different approaches to check if an element exists in an array or map:

1. `Array some`: This approach uses the `some()` method on the input array to check if any element matches a condition (in this case, the existence of an element with the same `id` in the reference array).
2. `Map has`: This approach uses the `has()` method on a Map object to check if a key (element's `id`) exists.

**Options Compared**

The two approaches being compared are:

1. Using the `some()` method on an array
2. Using the `has()` method on a Map

**Pros and Cons of Each Approach:**

1. **Array some**:
	* Pros:
		+ Simple to implement, as it only requires iterating over the input array.
		+ Suitable for arrays with large numbers of elements.
	* Cons:
		+ Less efficient than `Map has` because it requires scanning the entire array.
2. **Map has**:
	* Pros:
		+ More efficient than `Array some`, especially when dealing with large datasets.
		+ Can be faster due to caching and lookups on a Map object.
	* Cons:
		+ Requires creating a temporary Map object, which may incur additional overhead.

**Library or Special JS Feature**

In this benchmark, no special JavaScript features or libraries are used beyond the standard `Map` and `Array` types. However, if we consider the `some()` method as a part of the standard library, it's still an interesting aspect to explore in terms of performance.

**Other Considerations**

When dealing with large datasets, the performance difference between these two approaches can be significant. In general:

* If you're working with arrays and need to check if any element matches a condition, using `some()` might be a good choice.
* When working with maps and need to look up specific keys, `has()` is usually a better option.

**Alternatives**

Other alternatives for this kind of benchmark include:

1. Using other methods on the input array or map, such as `every()`, `find()`, or `includes()`.
2. Implementing a custom function to check for element existence.
3. Using a different data structure altogether, like a Set or an object with specific properties.

For this particular benchmark, measuring the performance difference between using `some()` and `Map has` provides valuable insights into how JavaScript engines handle array and map operations.

Related benchmarks:

Map has vs array some in loop (version: 0)

Comparing performance of: Array some vs Map has

Created: 4 years ago by: Guest

Jump to the latest result

Array some

Map has

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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