Benchmark: map vs splice test

Tests:

map
const events = []; let max = 1000; while (max > 0) { events.push({ id: max, title: `t ${max}`}); max --; } const event = { id: 500, title: 'foo' }; const index = events.findIndex((el) => el.id === event.id); let updated; if (index === -1) { updated = events.map((el) => el.id === event.id ? event : el); } else { updated = [ ...events, event ]; }
slice
const events = []; let max = 1000; while (max > 0) { events.push({ id: max, title: `t ${max}`}); max --; } const event = { id: 500, title: 'foo' }; const index = events.findIndex((el) => el.id === event.id); let updated; if (index === -1) { updated = [ ...events.slice(0, index), event, ...events.slice(index + 1) ]; } else { updated = [ ...events, event ]; }

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
map
slice

Fastest: N/A

Slowest: N/A

Latest run results:

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

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/130.0.0.0 Safari/537.36

Browser/OS: Chrome 130 on Windows

View result in a separate tab

Test name	Executions per second
map	78247.8 Ops/sec
slice	85965.7 Ops/sec

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

LLMs can make mistakes. Check important info.

Let's break down the provided JSON data and explain what is tested, compared options, pros and cons of those approaches, and other considerations.

**Benchmark Definition**

The benchmark is testing two different approaches to update an array of objects when a specific element is found. The test cases are:

1. Using `map()` method.
2. Using `slice()` method.

**Test Cases**

For each test case, we have a similar setup:

* An empty array `events` is created and populated with 1000 elements.
* A target element `event` is defined with an `id` of 500.
* The `findIndex()` method is used to find the index of the target element in the `events` array.

**Option Comparison**

The two options being compared are:

1. **Map() Method**: This approach creates a new array with the updated elements, using the spread operator (`...`) to copy the existing elements and add the new one.
2. **Slice() Method**: This approach uses `slice()` method to create a shallow copy of the original array up to the index of the target element, adds the new element at that position, and then concatenates the remaining elements.

**Pros and Cons**

**Map() Method:**

Pros:

* More concise and expressive code.
* Creates a new array with the updated elements, which can be beneficial for performance in some cases (e.g., when dealing with large arrays).

Cons:

* Creates an additional copy of the original array, which can lead to increased memory usage.

**Slice() Method:**

Pros:

* Avoids creating an additional copy of the original array.
* Can be more efficient in terms of memory usage.

Cons:

* Requires using multiple `slice()` calls and concatenation, making the code slightly less concise.
* May be slower due to the overhead of multiple function calls and concatenation.

**Other Considerations**

In this specific benchmark, it appears that the `slice()` method is performing better than the `map()` method on this particular test case. However, this may vary depending on the specific use case and requirements.

Another consideration is that both methods modify the original array in place, which can be beneficial for performance if working with large arrays or iterative processes.

**JavaScript Features**

In this benchmark, we don't see any special JavaScript features being used, such as arrow functions, async/await, or promises. However, it's worth noting that some modern browsers may have optimized `map()` and `slice()` methods due to their widespread use in web development.

**Alternatives**

If you're looking for alternative approaches to update an array of objects when a specific element is found, you could consider using:

1. **Filter() Method**: Similar to `map()`, but creates a new array with only the elements that pass the test.
2. **Splice() Method**: Modifies the original array in place by removing or replacing elements at a specified index.
3. **Using a Library**: Depending on your specific use case, you might consider using a library like Lodash, which provides a range of utility functions for working with arrays and objects.

Keep in mind that each approach has its own trade-offs in terms of performance, memory usage, and readability.

Related benchmarks:

map vs splice test (version: 0)

Comparing performance of: map vs slice

Created: 3 years ago by: Guest

Jump to the latest result

map

slice

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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