Benchmark: {} vs Map Creation

HTML Preparation code:

<!--your preparation HTML code goes here-->

Tests:

Creation: Object
const n = []; for (let i = 0; i < 10000; i++) { n.push({}); }
Creation: Map
const n = []; for (let i = 0; i < 10000; i++) { n.push(new Map()); }

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Creation: Object
Creation: Map

Fastest: N/A

Slowest: N/A

Latest run results:

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

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:136.0) Gecko/20100101 Firefox/136.0

Browser/OS: Firefox 136 on Windows

View result in a separate tab

Test name	Executions per second
Creation: Object	15842.7 Ops/sec
Creation: Map	8847.1 Ops/sec

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

LLMs can make mistakes. Check important info.

In this benchmark, we compare two methods of creating collections in JavaScript: creating plain objects versus creating instances of the `Map` object. Each method has its context, advantages, and disadvantages, which can impact performance and ease of use based on the specific requirements of a project.

### Test Cases Overview

1. **Creation: Object**
   - **Benchmark Code**: 
     ```javascript
     const n = [];
     for (let i = 0; i < 10000; i++) {
         n.push({});
     }
     ```
   - **Description**: This test case measures the performance of creating 10,000 plain JavaScript objects and pushing them into an array.

2. **Creation: Map**
   - **Benchmark Code**: 
     ```javascript
     const n = [];
     for (let i = 0; i < 10000; i++) {
         n.push(new Map());
     }
     ```
   - **Description**: This test case measures the performance of creating 10,000 instances of the `Map` object and pushing them into an array.

### Performance Results

Based on the latest benchmark results:
- **Creation: Object**
  - **Executions Per Second**: 21,197.77
- **Creation: Map**
  - **Executions Per Second**: 4,676.49

From the results, we can see that creating plain objects is significantly faster than creating instances of `Map` in this specific scenario.

### Pros and Cons

#### Plain Objects
- **Pros**:
  - **Performance**: As illustrated, creating objects is more performant; they are lightweight and have less overhead compared to `Map`.
  - **Simplicity**: They are straightforward to use for generic key-value pair storage when you don't need advanced features.
  
- **Cons**:
  - **Limited Features**: Objects do not maintain the order of keys, and keys can only be strings (or symbols), which limits their flexibility.
  - **Prototype Inheritance**: If not handled properly, they can carry inherited properties from their prototype chain, which can lead to unexpected behavior.

#### Maps
- **Pros**:
  - **Key Flexibility**: Supports both objects and primitive values as keys, which can be beneficial in certain use cases.
  - **Order of Entries**: Maps maintain the order of their elements, which is useful when order matters.
  - **Built-in Methods**: Offers methods like `set`, `get`, and `delete`, which make operations on collections more versatile.

- **Cons**:
  - **Performance**: As the benchmark shows, the creation of `Map` instances is slower than creating objects.
  - **Memory Overhead**: `Map` instances generally use more memory than plain objects due to their additional features.

### Other Alternatives
- **Arrays**: In some situations, using an array of tuples (or arrays with two elements) can replicate the functionality of objects or Maps while maintaining order. However, this approach has its own pros and cons regarding access speed and clarity.
  
- **WeakMap/WeakSet**: If it’s necessary to manage memory more effectively, particularly with large collections that won't be needed again, options like `WeakMap` or `WeakSet` can be considered. These can automatically clean up when there are no more references to their keys.

### Conclusion
In conclusion, this benchmark provides valuable insights into the performance implications of using plain objects versus `Map` for collection creation in JavaScript. While developers may lean towards `Map` for its features and capabilities, when performance is critical (e.g., creating many instances), plain objects might be the better choice. Understanding the characteristics of each can help developers make informed decisions based on their specific use cases and requirements.

Related benchmarks:

{} vs Map Creation (version: 3)

Comparing performance of: Creation: Object vs Creation: Map

Created: one year ago by: Registered User

Jump to the latest result

Creation: Object

Creation: Map

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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