Benchmark: map vs splice1 - MeasureThat.net

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.slice(0, index), event, ...events.slice(index + 1) ]; } 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:

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

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Let's dive into the benchmark.

The provided JSON represents two individual test cases for measuring JavaScript performance, specifically comparing `Array.prototype.map()` and `Array.prototype.slice()`. These methods are commonly used to manipulate arrays in JavaScript.

**Options being compared:**

1.  **`map()`**: This method creates a new array with the results of applying a provided function on every element in this array.
2.  **`slice()`**: This method returns a shallow copy of a portion of an array into a new array object.

**Pros and Cons of each approach:**

*   **`map()`**
    *   Pros:
        *   More concise and readable
        *   Can be more efficient for large arrays because it avoids the overhead of creating multiple intermediate arrays (although this can depend on the specific use case)
    *   Cons:
        *   Creates a new array, which may consume additional memory
*   **`slice()`**
    *   Pros:
        *   More control over the output array (can be used to modify the original array)
        *   Can be more efficient for small arrays or when avoiding memory allocation is important
    *   Cons:
        *   May be less concise and readable due to the need for explicit indexing

**Library and its purpose:**

The benchmark uses JavaScript's built-in `Array.prototype` methods, specifically `map()` and `slice()`, which are part of the standard library. These methods are widely supported across different browsers and environments.

**Special JS feature or syntax:**

There is no special JavaScript feature or syntax used in this benchmark. It only utilizes the standard features and methods available in modern JavaScript implementations.

The test case prepares an array of objects with increasing IDs, finds the index of a specific event object within the array using `findIndex()`, and then updates the array by either replacing the original element at the found index with the new event object (using `map()`) or by creating a new array with the updated elements (using `slice()`).

**Other alternatives:**

In addition to `map()` and `slice()`, other methods for manipulating arrays could be used, such as:

*   Using `forEach()` in combination with an array of functions
*   Using libraries like Lodash or Ramda for more concise array manipulation code
*   Implementing custom array manipulations using loops

However, these alternatives may not provide the same level of performance or memory efficiency as the built-in methods used in this benchmark.

Related benchmarks:

map vs splice1 (version: 0)

Comparing performance of: map vs slice

Created: 5 years ago by: Guest

Jump to the latest result

map

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):