Benchmark: add objects to array v2

Script Preparation code:

src = {}
for (let ki = 0; ki < 32; ++ki)
{
  k = 'key_' + ki
  src[k] = undefined
}

function copyObject(o)
{
  return {...o}	// shallow copy
}

numInsertions = 10000

Tests:

append via push
a = [] for (let i = 0; i < numInsertions; ++i) { a.push(copyObject(src)) }
prepend via splice
a = [] for (let i = 0; i < numInsertions; ++i) { a.splice(0,0,copyObject(src)) }
prepend via unshift
a = [] for (let i = 0; i < numInsertions; ++i) { a.unshift(copyObject(src)) }

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
append via push
prepend via splice
prepend via unshift

Fastest: N/A

Slowest: N/A

Latest run results:

No previous run results

This benchmark does not have any results yet. Be the first one to run it!

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

LLMs can make mistakes. Check important info.

Let's dive into the world of JavaScript microbenchmarks on MeasureThat.net.

**Benchmark Definition JSON**

The benchmark definition represents a single test case, which is designed to measure the performance of appending or prepending elements to an array using different methods: `push`, `splice`, and `unshift`.

Here's what's being tested:

1. **Array Initialization**: The script prepares an empty object `src` with 32 keys, each initialized to `undefined`. This object is used as a data source for the test case.
2. **Copy Object Function**: A custom function `copyObject(o)` is defined to perform a shallow copy of an object. In this case, it simply returns a new object with the same properties using the spread operator (`{...o}`).
3. **Number of Insertions**: The script sets a variable `numInsertions` to 10,000, which determines the number of times the array is populated with copied objects.

**Options Compared**

Three different approaches are being compared:

1. **Append via Push**: Elements are appended to the end of the array using the `push()` method.
2. **Prepend via Splice**: Elements are prepended to the beginning of the array using the `splice(0, 0, ...)` method.
3. **Prepend via Unshift**: Elements are prepended to the beginning of the array using the `unshift()` method.

**Pros and Cons**

Each approach has its pros and cons:

*   **Append via Push**:
    *   Pros: Simple and efficient, as it only requires a single operation on the array.
    *   Cons: May not be as performant for large arrays or when elements need to be inserted at specific positions.
*   **Prepend via Splice**: 
    *   Pros: Allows for more control over element insertion, including prepending multiple elements at once.
    *   Cons: More complex and potentially slower due to the additional operation on the array.
*   **Prepend via Unshift**:
    *   Pros: Similar to `push`, but with better performance when dealing with large arrays or frequent insertions.
    *   Cons: May not be as flexible as `splice` for more complex insertion scenarios.

**Library and Syntax**

In this benchmark, the custom `copyObject(o)` function is used to create shallow copies of the source object. This approach assumes that the objects being copied have a simple structure with no nested arrays or recursive references.

No special JavaScript features or syntax are required for this benchmark. The focus is solely on measuring the performance of array manipulation methods.

**Alternative Approaches**

Other approaches could be explored, such as:

*   Using `Array.prototype.reduce()` to prepend elements
*   Utilizing `array.map()` and `concat()` for prepending elements
*   Implementing a custom insertion algorithm using bitwise operations or other techniques

Keep in mind that these alternative approaches may not be as straightforward or efficient as the original methods being compared.

Related benchmarks:

add objects to array v2 (version: 1)

Comparing performance of: append via push vs prepend via splice vs prepend via unshift

Created: 3 years ago by: Registered User

Jump to the latest result

append via push

prepend via splice

prepend via unshift

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):