Benchmark: slice vs filter in js2

Script Preparation code:

var a = [{ title: '1' }, { title: '2' }, { title: '3' }]

Tests:

filter
return a.filter((obj) => obj.title != '1' && obj.title != '3')
slice
return a.slice(1,2)

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
filter
slice

Fastest: N/A

Slowest: N/A

Latest run results:

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

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Let's dive into explaining the benchmark.

The provided JSON represents a JavaScript microbenchmark that compares two different approaches for filtering and slicing arrays: `filter` and `slice`. The benchmark is designed to measure which approach is faster in modern web browsers.

**Options compared:**

1. **Array.prototype.filter()**: This method creates a new array with all elements that pass the test implemented by the provided function.
2. **Array.prototype.slice()**: This method creates a shallow copy of a portion of an array, starting from the beginning (index 0) and ending at the specified index (exclusive).

**Pros and Cons:**

1. **filter()**:
	* Pros:
		+ More efficient for filtering arrays with many elements because it only iterates over the elements that need to be kept.
		+ Can handle null, undefined, or other values in addition to matching values.
	* Cons:
		+ Creates a new array, which can be memory-intensive for large datasets.
		+ May have performance overhead due to function call and evaluation.
2. **slice()**:
	* Pros:
		+ Faster because it doesn't create a new array; instead, it returns a reference to the original array's element.
		+ More suitable for small arrays or when memory efficiency is crucial.
	* Cons:
		+ Only works with non-negative indices and can be slow if the start index is large.
		+ May not work correctly if the end index is negative.

**Other considerations:**

1. **Array methods**: Both `filter()` and `slice()` are part of the Array.prototype. This means they're built-in methods, which might affect performance compared to using custom implementations or other libraries.
2. **Browser differences**: The benchmark results show that Chrome 85 on Windows Desktop has different execution speeds for each test case.

**Library usage:**

None in this example. Both `filter()` and `slice()` are part of the JavaScript standard library, so no external libraries are required.

**Special JS feature or syntax:**

There are no special features or syntax mentioned in the benchmark definition or test cases. The focus is solely on comparing two built-in array methods.

**Alternatives:**

If you're interested in exploring alternative approaches for filtering and slicing arrays, here are some options:

1. **Using a custom implementation**: You can write your own iterative solution using a `for` loop to compare the performance of `filter()` and `slice()`.
2. **Other array methods**: Consider using other built-in Array.prototype methods like `map()`, `reduce()`, or `forEach()` for filtering arrays.
3. **Third-party libraries**: If you need more advanced filtering capabilities, consider using a library like Lodash or Ramda.

Keep in mind that the choice of approach depends on your specific use case, performance requirements, and personal preference.

Related benchmarks:

slice vs filter in js2 (version: 0)

Comparing performance of: filter vs slice

Created: 5 years ago by: Guest

Jump to the latest result

filter

slice

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

No previous run results

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