Benchmark: Create Map/Set vs reuse Map/Set

Script Preparation code:

var list = Array(500).fill(1).map((x, i) => x + i);
var entries = list.map(x => [x, true]);

var globalMap = new Map();
var globalSet = new Set();

Tests:

Create Map
var map = new Map(entries);
Create Set
var set = new Set(list);
Reuse Map
globalMap.clear(); entries.forEach(x => globalMap.set(x[0], x[1]));
Reuse Set
globalSet.clear(); list.forEach(x => globalSet.add(x));

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Create Map
Create Set
Reuse Map
Reuse Set

Fastest: N/A

Slowest: N/A

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

LLMs can make mistakes. Check important info.

Measuring performance differences between various approaches is crucial in software development, especially when considering data structures like Maps and Sets.

**Benchmark Overview**

The provided benchmark measures the execution time of three different approaches:

1. Creating a new Map from scratch (Create Map)
2. Creating a new Set from scratch (Create Set)
3. Reusing an existing Map (Reuse Map) or Set (Reuse Set)

**Approach 1: Create Map and Create Set**

These two approaches involve creating a new instance of the Map or Set data structure from a predefined list.

* **Pros:** Creating a new Map or Set is often necessary when working with external data, and it provides a fresh start. This approach allows for easy modification and extension of the data.
* **Cons:** Creating a new Map or Set can be slower than reusing an existing one, especially if the underlying data structure needs to be rebuilt.

**Approach 2: Reuse Map and Reuse Set**

These two approaches involve modifying an existing Map (or Set) by clearing it and then adding entries.

* **Pros:** Reusing an existing Map or Set can be faster than creating a new one, as it eliminates the overhead of building a new data structure. This approach is particularly useful when working with large datasets.
* **Cons:** Modifying an existing Map or Set can lead to performance issues if the underlying data structure becomes too complex or fragmented.

**Library and Purpose**

The `Map` and `Set` data structures are built-in JavaScript collections that provide efficient ways to store and manipulate key-value pairs (Maps) or unique values (Sets).

* **Map:** A Map is a data structure that stores key-value pairs, where each key is unique and maps to a specific value. Maps are useful for storing and manipulating complex data.
* **Set:** A Set is a data structure that stores unique values, without any ordering or duplicate values. Sets are useful for removing duplicates and performing membership tests.

**Special JavaScript Feature**

There is no special JavaScript feature mentioned in the benchmark definition, but it's worth noting that some features like `let` and `const` declarations can affect performance by changing the behavior of the JavaScript engine.

**Alternative Approaches**

Other approaches to create or reuse Maps and Sets include:

* Using an external library or framework, such as Lodash or Immutable.js
* Implementing a custom data structure using a different approach, like a hash table or a linked list
* Using a caching mechanism to store frequently used Maps or Sets

In conclusion, the benchmark highlights the importance of considering performance when working with data structures like Maps and Sets. By understanding the pros and cons of each approach, developers can choose the most efficient solution for their specific use case.

Latest run results:

Run details: (Test run date: 3 years ago)

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 11_2_3) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/89.0.4389.128 Safari/537.36

Browser/OS: Chrome 89 on Mac OS X 11.2.3

View result in a separate tab

Test name	Executions per second
Create Map	41799.6 Ops/sec
Create Set	48872.5 Ops/sec
Reuse Map	25036.0 Ops/sec
Reuse Set	25403.8 Ops/sec

Related benchmarks:

Create Map/Set vs reuse Map/Set (version: 0)

Comparing performance of: Create Map vs Create Set vs Reuse Map vs Reuse Set

Created: 3 years ago by: Registered User

Jump to the latest result

Create Map

Create Set

Reuse Map

Reuse Set

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):