Benchmark: Remove first element from array - slice vs filter

Script Preparation code:

var test = Array.from({ length: 10000 }, (_, index) => ({ id: index + 1, value: Math.random() }))

Tests:

slice
test.slice(1)
filter
test.filter((e, i) => i !== 0 )

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
slice
filter

Fastest: N/A

Slowest: N/A

Latest run results:

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

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/132.0.0.0 Safari/537.36

Browser/OS: Chrome 132 on Mac OS X 10.15.7

View result in a separate tab

Test name	Executions per second
slice	2033054.4 Ops/sec
filter	34609.0 Ops/sec

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

LLMs can make mistakes. Check important info.

Let's dive into the explanation.

The provided JSON represents a JavaScript microbenchmark test case on the MeasureThat.net website. The test measures the performance of two different approaches to remove the first element from an array: using the `slice()` method and the `filter()` function.

**Approaches compared:**

1. **`slice()`**: This method returns a new array that includes all elements except the first one. It creates a new array object with the specified length, and then fills it with elements from the original array.
2. **`filter()`**: This method creates a new array with all elements that pass the provided test. In this case, the filter function checks if the index `i` is not equal to 0.

**Pros and Cons:**

*   **`slice()`**:
    *   Pros: It's generally faster because it uses an optimization technique called "overlapping slices," which reduces memory allocation and copying.
    *   Cons: Creating a new array object can be expensive in terms of memory allocation and garbage collection.
*   **`filter()`**:
    *   Pros: It avoids creating a new array, reducing memory allocation and garbage collection overhead. However, it may incur additional overhead due to the creation of an iterator and the filtering process.
    *   Cons: The filtering process can be slower than `slice()`, especially for large arrays.

The choice between these two approaches depends on the specific use case and performance requirements. If memory efficiency is crucial, `filter()` might be a better option. However, if raw speed is essential, `slice()` might be preferred.

**Library usage:**

None of the provided code snippet uses any external libraries for this test case.

**Special JavaScript features or syntax:**

No special JavaScript features or syntax are used in this benchmark.

Now, let's consider some alternative approaches:

*   **Using a library like Lodash**: If you need to perform array operations frequently, using a library like Lodash can provide additional performance benefits and simplify your code. However, this would require including an external dependency.
*   **Using a custom implementation**: Depending on the specific requirements of your project, you might be able to optimize the `slice()` and `filter()` methods further by implementing them from scratch. This approach requires more expertise in JavaScript internals and can lead to a significant increase in development time.

These alternatives are worth considering when dealing with performance-critical array operations in JavaScript.

Related benchmarks:

Remove first element from array - slice vs filter (version: 0)

Comparing performance of: slice vs filter

Created: 2 years ago by: Guest

Jump to the latest result

slice

filter

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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