Benchmark: slice vs subarray vs set

Script Preparation code:

var data = [1, 2, 3, 4, 5, 6, 7, 8, 9, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 1, 2, 3, 4, 5, 6, 7, 8, 9, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9];
var f32 = new Float32Array(data);

Tests:

subarray direct
var copy = f32.subarray(10, 20);
slice direct
var copy = f32.slice(10, 20);
subarray copy
var copy = new Float32Array(f32.subarray(10, 20));
slice copy
var copy = new Float32Array(f32.slice(10, 20));
subarray set
var copy = new Float32Array(10).set(f32.subarray(10, 20));
slice set
var copy = new Float32Array(10).set(f32.slice(10, 20));

Historical Performance Data aggregated from 90 community runs

Desktop Results:

Chrome 62 runs

subarray direct

16.6M/s

slice direct

12.8M/s

subarray copy

6.8M/s

subarray set

6.4M/s

slice copy

6.1M/s

slice set

5.7M/s

Fastest: subarray direct (2.9x faster)

View exact numbers

✓ subarray direct: 16,629,372 ops/sec
• slice direct: 12,806,486 ops/sec
• subarray copy: 6,807,290 ops/sec
• subarray set: 6,428,821 ops/sec
• slice copy: 6,088,337 ops/sec
• slice set: 5,710,804 ops/sec

Firefox 17 runs

slice direct

17.4M/s

subarray direct

11.0M/s

slice set

10.2M/s

slice copy

8.2M/s

subarray set

8.2M/s

subarray copy

7.2M/s

Fastest: slice direct (2.4x faster)

View exact numbers

✓ slice direct: 17,388,642 ops/sec
• subarray direct: 10,989,613 ops/sec
• slice set: 10,243,935 ops/sec
• slice copy: 8,245,592 ops/sec
• subarray set: 8,152,702 ops/sec
• subarray copy: 7,171,802 ops/sec

Safari 6 runs

subarray direct

27.1M/s

slice direct

23.7M/s

subarray copy

15.9M/s

slice set

15.2M/s

slice copy

14.0M/s

subarray set

11.7M/s

Fastest: subarray direct (2.3x faster)

View exact numbers

✓ subarray direct: 27,083,918 ops/sec
• slice direct: 23,739,056 ops/sec
• subarray copy: 15,868,230 ops/sec
• slice set: 15,164,654 ops/sec
• slice copy: 13,995,140 ops/sec
• subarray set: 11,703,284 ops/sec

Mobile Results:

Safari 5 runs

subarray direct

14.7M/s

slice direct

14.0M/s

subarray copy

6.7M/s

subarray set

6.5M/s

slice copy

6.3M/s

slice set

6.1M/s

Fastest: subarray direct (2.4x faster)

View exact numbers

✓ subarray direct: 14,691,080 ops/sec
• slice direct: 14,023,545 ops/sec
• subarray copy: 6,740,940 ops/sec
• subarray set: 6,509,514 ops/sec
• slice copy: 6,259,449 ops/sec
• slice set: 6,121,524 ops/sec

Results show median performance across all community submissions. Run this benchmark yourself to verify on your device.

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
subarray direct
slice direct
subarray copy
slice copy
subarray set
slice set

Fastest: N/A

Slowest: N/A

Latest run results:

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

User agent: Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/137.0.0.0 Safari/537.36

Browser/OS: Chrome 137 on Linux

View result in a separate tab

subarray direct

20.0M/s

slice direct

15.8M/s

subarray set

11.3M/s

subarray copy

10.1M/s

slice set

9.7M/s

slice copy

9.3M/s

View exact numbers

Test name	Executions per second
✓ subarray direct	19,992,284 Ops/sec
slice direct	15,777,429 Ops/sec
subarray set	11,258,312 Ops/sec
subarray copy	10,085,197 Ops/sec
slice set	9,724,500 Ops/sec
slice copy	9,348,755 Ops/sec

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

LLMs can make mistakes. Check important info.

**Benchmark Overview**

The provided benchmark compares the performance of three approaches to create a subset of an array in JavaScript: `subarray()`, `slice()`, and creating a new array using `set()`.

**Options Compared**

1. **`subarray()`**: This method creates a new array containing the elements from the original array, starting at the specified index (10) and ending at the specified end index (20).
2. **`slice()`**: Similar to `subarray()`, but returns a shallow copy of the specified range of elements in the original array.
3. **`subarray()` + `new Float32Array()`**: Creates a new `Float32Array` instance from the subset of the original array using `subarray()`.
4. **`slice()` + `new Float32Array()`**: Similar to the previous option, but uses `slice()` instead of `subarray()`.

**Pros and Cons**

* **`subarray()`**: Creates a new array, which can be inefficient if the resulting array is smaller than the original.
* **`slice()`**: Returns a shallow copy of the specified range of elements, which can lead to performance issues if the copied array needs to be modified later.
* **`subarray()` + `new Float32Array()`**: Creates a new `Float32Array` instance from the subset, which is more memory-efficient than creating a full array using `slice()`.
* **`slice()` + `new Float32Array()`**: Similar to the previous option, but uses `slice()` instead of `subarray()`.

**Library and Special Features**

None mentioned in the provided benchmark.

**Other Considerations**

* The benchmark only tests the performance of these four approaches, so other factors like memory allocation or garbage collection may not be considered.
* The test data is a large array with duplicate values, which can impact performance due to caching effects.

**Alternatives**

If you need to create an array subset in JavaScript, consider using `Array.prototype.slice()` or `Array.prototype.subarray()`, as they are more efficient than creating a new array using `new Float32Array()`.

For more complex scenarios, you may want to explore other libraries like Lodash's `_.slice()` or _.tail(), which provide optimized implementations for common array operations.

slice vs subarray vs set (version: 0)

Comparing performance of: `subarray direct vs slice direct vs subarray copy vs slice copy vs subarray set vs slice set`

Created: 8 years ago by: Guest

Go to the latest result

subarray direct

slice direct

subarray copy

slice copy

subarray set

slice set

Historical Performance Data aggregated from 90 community runs

Desktop Results:

Chrome 62 runs

Firefox 17 runs

Safari 6 runs

Mobile Results:

Safari 5 runs

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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

slice vs subarray vs set (version: 0)

Comparing performance of: subarray direct vs slice direct vs subarray copy vs slice copy vs subarray set vs slice set

Created: 8 years ago by: Guest

Go to the latest result

subarray direct

slice direct

subarray copy

slice copy

subarray set

slice set

Historical Performance Data aggregated from 90 community runs

Desktop Results:

Chrome 62 runs

Firefox 17 runs

Safari 6 runs

Mobile Results:

Safari 5 runs

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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

Related benchmarks

Comparing performance of: `subarray direct vs slice direct vs subarray copy vs slice copy vs subarray set vs slice set`