Benchmark: Map.has vs Set.has

Script Preparation code:

var list = [];
for (let i = 0; i < 1000; i++) {
  list.push(i);
}
var set = new Set(list);
var map = new Map();
list.forEach(item => map.set(item, true));

Tests:

Set
var found = set.has(450);
Map
var found = map.has(450)

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Set
Map

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.

**What is being tested?**

The provided JSON represents a JavaScript microbenchmark test case that compares the performance of two methods: `has` on a `Set` data structure and `has` on a `Map` data structure.

**Options being compared:**

There are two options being compared:

1. **Set.has**: This method is used to check if an element exists in a `Set`. A `Set` in JavaScript is a collection of unique values, which means that duplicate elements are automatically removed.
2. **Map.has**: This method is used to check if a key exists in a `Map`. A `Map` in JavaScript is a collection of key-value pairs, where each key is unique and maps to a specific value.

**Pros and Cons:**

* **Set.has**:
	+ Pros:
		- Faster lookup time since sets are typically implemented as hash tables, which allow for O(1) average-case lookup.
		- More memory-efficient than `Map` since sets only store unique values.
	+ Cons:
		- May not work correctly if the set contains duplicate values that should be considered equal (e.g., two strings that represent the same Unicode code point).
* **Map.has**:
	+ Pros:
		- Can handle cases where the key is an object or a string, and can be used to check for existence of a value without having to know its exact index.
	+ Cons:
		- Generally slower than `Set.has` since maps are typically implemented as hash tables with additional overhead from storing keys and values.

**Library usage:**

The test case uses the `Set` and `Map` constructors, which are built-in JavaScript data structures. The `list.forEach` method is also used to populate the map.

**Special JS feature or syntax:**

There are no special JavaScript features or syntaxes being tested in this benchmark. However, it's worth noting that some browsers may have specific optimizations or implementations for these methods that could affect performance.

**Other alternatives:**

If you wanted to implement a custom set or map data structure instead of using the built-in `Set` and `Map` constructors, you might consider using an object with unique keys and values. However, this would likely incur significant performance overhead compared to using the optimized built-in implementations.

Here's an example of how you could implement a simple set data structure:
```javascript
class CustomSet {
  constructor() {
    this.values = {};
  }

has(value) {
    return value in this.values;
  }
}
```
However, this implementation would not be recommended for production use due to its lack of performance and memory efficiency compared to the built-in `Set` data structure.

Keep in mind that measuring the performance of different implementations or data structures can be a complex task, and results may vary depending on the specific use case and requirements.

Related benchmarks:

Map.has vs Set.has (version: 0)

Comparing performance of: Set vs Map

Created: 6 years ago by: Guest

Jump to the latest result

Set

Map

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):