Benchmark: ts4623 - MeasureThat.net

Tests:

f1_map
var map = new Map() for(let i=0;i<10000;i++){ const key = i+'_'+i; map.set(key, 'foo'); }
f2_map
var map = new Map() for(let i=0;i<10000;i++){ const key = (i << 16) | i; map.set(key, 'foo'); }
f1_obj
var map = {} for(let i=0;i<10000;i++){ const key = i+'_'+i; map[key] = 'foo' }
f2_obj
var map = {} for(let i=0;i<10000;i++){ const key = (i << 16) | i; map[key] = 'foo'; }

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
f1_map
f2_map
f1_obj
f2_obj

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 2 months ago)

User agent: Mozilla/5.0 (X11; Linux x86_64; rv:131.0) Gecko/20100101 Firefox/131.0

Browser/OS: Firefox 131 on Linux

View result in a separate tab

Test name	Executions per second
f1_map	647.3 Ops/sec
f2_map	1883.1 Ops/sec
f1_obj	406.5 Ops/sec
f2_obj	1196.9 Ops/sec

Autogenerated LLM Summary (model gpt-4o-mini, generated 2 months ago):

LLMs can make mistakes. Check important info.

The benchmark in question tests the performance of different approaches to storing key-value pairs in JavaScript, specifically focusing on two data structures: `Map` and plain JavaScript objects ({}). The benchmark contains four test cases, each comparing two different methods of generating keys for the values being stored. Here's a detailed breakdown of what is being tested:

### Test Cases Overview

1. **f1_map**: 
   - **Benchmark Definition**: Uses `Map` with keys generated as strings formed by concatenating the index with itself. 
   - **Key Format**: `i+'_'+i` which results in keys like "0_0", "1_1", "2_2", etc.

2. **f2_map**: 
   - **Benchmark Definition**: Uses `Map` with keys generated using bit manipulation (`(i << 16) | i`).
   - **Key Format**: This creates numeric keys where the higher bits represent the index and is more memory-efficient for numerical keys.

3. **f1_obj**: 
   - **Benchmark Definition**: Uses a plain object with the same string key generation as in **f1_map**.
   - **Key Format**: Same as **f1_map**, resulting in string keys.

4. **f2_obj**: 
   - **Benchmark Definition**: Uses a plain object with keys generated using bit manipulation like **f2_map**.
   - **Key Format**: Same numeric key generation method, optimized for numerical indices.

### Comparisons and Considerations

**1. Data Structure: Map vs Object**
  - **Map**: 
    - Pros:
      - Maintains the insertion order of keys.
      - Can use any value (objects, functions, etc.) as keys, not limited to strings.
      - More efficient for frequent additions/removals of key-value pairs.
    - Cons:
      - Potentially higher memory overhead compared to objects when used for a large number of entries.
      - Slightly slower for simple key-value storage compared to objects in some cases.
  
  - **Object**: 
    - Pros:
      - Simplicity and ease of use for basic key-value storage.
      - More lightweight overhead for keys that don’t need complex features (like order or varied key types).
    - Cons:
      - Only strings and symbols can be used as keys.
      - Performance may degrade with numerous properties due to prototype chain lookups.

**2. Key Generation Method: String vs Numeric Bit Manipulation**
  - **String Keys (`i+'_'+i`)**: 
    - Pros:
      - Human-readable and easier to debug.
      - Useful for cases where keys must be descriptive or identifiable.
    - Cons:
      - Generally involves more memory overhead due to string storage.
    
  - **Numeric Keys (`(i << 16) | i`)**: 
    - Pros:
      - More memory-efficient, especially advantageous when keys are numerically sequential.
      - Faster lookups on numeric comparisons.
    - Cons:
      - Less human-readable and harder to interpret if debugging is needed.

### Benchmark Results

From the benchmark results, we can see the following performance for each test:

- **f2_map** (using `Map` with numeric keys): Highest execution speed at approximately **1883.13 executions per second**.
- **f2_obj** (using Object with numeric keys): Second fastest at **1196.90 executions per second**.
- **f1_map** (using `Map` with string keys): Significantly slower at **647.31 executions per second**.
- **f1_obj** (using Object with string keys): Slowest at **406.48 executions per second**.

### Other Alternatives

- **Sets**: For scenarios where only keys (without associated values) are necessary, using `Set` could be more efficient.
- **WeakMap / WeakSet**: If memory management is a concern (especially in handling objects), these allow for garbage collection of unused keys.
- **Typed Arrays**: If performance is paramount and the data is numerical, considering typed arrays can result in significant performance improvements due to optimized underlying data handling.

In conclusion, the benchmark illustrates the trade-offs between `Map` and plain objects, highlighting the influence of key generation methods on performance, memory usage, and application logic design. These insights help software engineers make informed decisions when choosing data structures for handling key-value pairs in JavaScript applications.

Related benchmarks:

ts4623 (version: 0)

Comparing performance of: f1_map vs f2_map vs f1_obj vs f2_obj

Created: 2 months ago by: Guest

Jump to the latest result

f1_map

f2_map

f1_obj

f2_obj

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model gpt-4o-mini, generated 2 months ago):