Benchmark: Multiple shift versus Index

HTML Preparation code:

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

Script Preparation code:

const list = new Array(1000).fill("value");
const list2 = new Array(1000).fill("value");
const list3 = new Array(1000).fill("value");
const list4 = new Array(1000).fill("value");

Tests:

Move Indexes
let i = 100; while (i < 1000) { list[i - 100] = list[i]; i++; } list.length = 900;
Shift
let i = 0; while (i < 100) { list2.shift(); i++; }
Splice
list3.splice(0, 100);
Slice
list4.slice(100);

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Move Indexes
Shift
Splice
Slice

Fastest: N/A

Slowest: N/A

Latest run results:

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

User agent: Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/134.0.0.0 Safari/537.36

Browser/OS: Chrome 134 on Linux

View result in a separate tab

Test name	Executions per second
Move Indexes	189735.0 Ops/sec
Shift	1124463.4 Ops/sec
Splice	25837784.0 Ops/sec
Slice	3386710.2 Ops/sec

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

LLMs can make mistakes. Check important info.

The benchmark defined in the provided JSON tests the performance of various methods for modifying array data in JavaScript, specifically using a few different strategies for removing elements from the beginning of an array. This is a useful performance comparison, as handling large data sets effectively can greatly impact application efficiency.

### Options Compared:

1. **Move Indexes**:
   - **Code**: `let i = 100; while (i < 1000) { list[i - 100] = list[i]; i++; } list.length = 900;`
   - **Description**: This approach moves indexes of the array to effectively shift elements to the left by 100 positions. After processing the elements, it sets the length of the array to remove the now redundant elements.
   - **Pros**: 
     - It avoids the overhead of generating new arrays, which is typically more efficient for larger data sets.
   - **Cons**: 
     - It involves extra calculations and may be less readable than other methods.
  
2. **Shift**:
   - **Code**: `let i = 0; while (i < 100) { list2.shift(); i++; }`
   - **Description**: This approach uses the `shift()` method, which removes the first element from an array and reduces the array length.
   - **Pros**: 
     - Simple and intuitive to use; easy to understand for developers.
   - **Cons**: 
     - `shift()` is generally slow for large arrays as it requires re-indexing the remaining elements after each removal.

3. **Splice**:
   - **Code**: `list3.splice(0, 100);`
   - **Description**: This uses the `splice()` method to remove a specified number of elements starting from a given index (in this case, the start).
   - **Pros**: 
     - Can remove multiple elements at once.
     - More flexible, as it allows for nuanced array manipulation beyond just shifting.
   - **Cons**: 
     - Can be slower for large arrays due to the extra overhead of handling varying sizes of removed elements and re-indexing.

4. **Slice**:
   - **Code**: `list4.slice(100);`
   - **Description**: The `slice()` method creates a new array containing the elements from the specified start index onward. In this case, elements before the 100th index are not included in the new array.
   - **Pros**: 
     - Does not mutate the original array, which could be beneficial regarding immutability in certain programming paradigms.
   - **Cons**: 
     - It creates a new array, which can lead to increased memory usage and potential garbage collection overhead.

### Considerations:
- **Performance**: As observed from the benchmark results, the performance of these methods can vary significantly under different contexts, particularly with large arrays. For instance, `splice()` and `slice()` generally perform better than `shift()` as they do not involve repeated index recalculations after each operation.
- **Readability vs. Efficiency**: Some methods like `shift()` are more straightforward but less efficient. On the other hand, methods like "Move Indexes" may require more complex logic which can reduce code readability.
- **Memory Management**: Methods that create new arrays can increase memory usage, while methods that mutate existing arrays can lead to potential issues if there's a need to preserve original data.

### Alternative Approaches:
- **Using a Deque (Double-Ended Queue)**: For scenarios where frequent add/remove operations occur at both ends, a deque could provide better performance characteristics than standard arrays.
- **Linked Lists**: In cases where dynamic resizing and frequent additions or removals from both ends are required, a linked list could be more efficient compared to array manipulation.
- **Immutable.js or similar libraries**: Libraries like Immutable.js provide data structures that help manage operations with immutability. They come with performance optimizations specifically for handling large data arrays and could be a useful alternative for applications that require a functional programming approach.

In conclusion, the benchmarking results indicate the trade-offs among methods for removing elements from arrays in JavaScript, emphasizing the need for developers to select the most appropriate method based on both performance requirements and code maintainability.

Related benchmarks:

Multiple shift versus Index (version: 2)

Comparing performance of: Move Indexes vs Shift vs Splice vs Slice

Created: 2 months ago by: Registered User

Jump to the latest result

Move Indexes

Shift

Splice

Slice

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):