Benchmark: Hashmap.has vs Array.Filter

Script Preparation code:

const counter = 10000
const map = new Map()
const array = new Array(counter)

window.counter = counter
window.map = map
window.array = array
for (let i = 0; i < counter; i++) {
    map.set(i)
    array[i] = i
}

Tests:

Hashmap
window.map.has(500)
Array.filter
window.array.filter((value) => value === 500)

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Hashmap
Array.filter

Fastest: N/A

Slowest: N/A

Latest run results:

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

User agent: Mozilla/5.0 (Linux; Android 10; K) AppleWebKit/537.36 (KHTML, like Gecko) SamsungBrowser/28.0 Chrome/130.0.0.0 Mobile Safari/537.36

Browser/OS: Chrome Mobile 130 on Android

View result in a separate tab

Hashmap

125.7M/s

Array.filter

39K/s

View exact numbers

Test name	Executions per second
✓ Hashmap	125,688,696 Ops/sec
Array.filter	38,952 Ops/sec

Autogenerated LLM Summary (model gpt-4o-mini, generated one year ago):

LLMs can make mistakes. Check important info.

The benchmark you provided tests two different methods of querying data from collections in JavaScript: the `Map.prototype.has` method as implemented in the `Map` object, and the `Array.prototype.filter` method used on a native JavaScript array. The goal is to compare the performance of these two approaches for checking if a specific value exists.

### Options Compared:
1. **Hashmap (Map Object):** 
   - **Test Case:** `window.map.has(500)`
   - This involves using the `has` method of a `Map` object to check whether a specific key (in this case, `500`) exists in the `Map`.

2. **Array Filter:**
   - **Test Case:** `window.array.filter((value) => value === 500)`
   - This test case uses the `filter` method of an array, which iterates through the entire array and creates a new array containing all elements that satisfy the condition specified in the callback (i.e., being equal to `500`).

### Pros and Cons:

#### Hashmap (Map Object)
- **Pros:**
  - Fast lookups. The `Map.has` method operates in constant time O(1) on average because it uses a hash table structure internally.
  - Efficient when dealing with a large number of entries, especially when frequent lookups are needed.
  - A `Map` can hold any type of key (including objects), providing more flexibility.

- **Cons:**
  - Requires some upfront memory allocation, which might be less efficient for small datasets.
  - Slightly more overhead compared to simple arrays when creating and populating the map.

#### Array Filter
- **Pros:**
  - Simple and straightforward syntax for filtering data based on conditions.
  - Array methods are part of the core JavaScript API, making them widely supported and understood.

- **Cons:**
  - Performance can degrade significantly with large arrays, as the `filter` method has a time complexity of O(n) because it must check every element in the array.
  - Creates and returns a new array, which can lead to increased memory consumption.
  - If the goal is solely to check for existence rather than filtering, it's inefficient since it processes all elements.

### Libraries/Features:
This benchmark does not utilize any external libraries; it tests native JavaScript features. The features being tested (i.e., `Map` and `Array.filter`) are standard JavaScript functionalities provided by the language, designed for efficient data manipulation.

### Other Considerations:
- **Use Cases:** If you only need to check existence, `Map` is generally preferred due to its speed. If you're needing to not only check existence but also gather items that meet certain criteria, the `filter` method is appropriate.
- **Alternatives:** Other alternatives for managing collections could involve:
  - Using plain objects (`{}`) if keys are strings or symbols.
  - Using other searching techniques, like using a `Set` for existence checks (e.g., `Set.has()`), which also provides O(1) time complexity for lookups.
  - Depending on the context, using libraries like Lodash, which offers utility functions for manipulation and querying of collections but typically adds weight.

In conclusion, this benchmark illustrates a significant performance difference between two common JavaScript approaches for checking value existence: the `Map` object is faster for lookups compared to filtering an array, especially as the dataset size grows.

Hashmap.has vs Array.Filter (version: 2)

Comparing performance of: `Hashmap vs Array.filter`

Created: one year ago by: Registered User

Go to the latest result

Hashmap

Array.filter

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model gpt-4o-mini, generated one year ago):

Hashmap.has vs Array.Filter (version: 2)

Comparing performance of: Hashmap vs Array.filter

Created: one year ago by: Registered User

Go to the latest result

Hashmap

Array.filter

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model gpt-4o-mini, generated one year ago):

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Comparing performance of: `Hashmap vs Array.filter`