Benchmark: push-spread or splice performance

Script Preparation code:

var a1 = [];
var a2 = [];
var a3 = [];
var b = [];
var N = 10000;
for (let i = 0; i < N; i++) {
    a1.push(i);
    a2.push(i);
    a3.push(i);
    b.push(N - i);
}

Tests:

push-spread
a1.length = 0; a1.push(...b);
splice
a2.splice(0, a1.length, ...b);
new array
a3 = [...b];

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
push-spread
splice
new array

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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**Overview**

The provided JSON represents a benchmark test created on MeasureThat.net, which compares the performance of three different approaches to spread or concatenate arrays in JavaScript: using `push` followed by `spread`, using `splice`, and creating a new array using the spread operator (`...`). The test also includes a script preparation code that initializes four empty arrays and populates them with values.

**Benchmark Definition**

The benchmark definition is a JSON object that describes the test. In this case, it contains three individual test cases:

1. **Push-Spread**: This test case uses the `push` method followed by the spread operator (`...`) to concatenate two arrays.
2. **Splice**: This test case uses the `splice` method with the first argument set to 0 and the second argument set to the length of the original array, then uses the spread operator to concatenate the two arrays.
3. **New Array**: This test case creates a new array using the spread operator (`...`) to concatenate the two input arrays.

**Options Compared**

The three options compared in this benchmark are:

1. **Push-Spread**: Using `push` followed by the spread operator (`...`) to concatenate arrays.
2. **Splice**: Using the `splice` method with the first argument set to 0 and the second argument set to the length of the original array, then using the spread operator to concatenate the two arrays.
3. **New Array**: Creating a new array using the spread operator (`...`) to concatenate the input arrays.

**Pros and Cons**

Here's a brief analysis of each approach:

* **Push-Spread**:
	+ Pros: Simple and straightforward implementation. Can be efficient if the arrays are large.
	+ Cons: May not be as efficient as other approaches when dealing with small arrays, as it requires an extra push operation.
* **Splice**:
	+ Pros: Can be more efficient than `push` followed by spread for small arrays, as it avoids the extra push operation. However, it may be slower for larger arrays due to the overhead of the `splice` method.
	+ Cons: Requires a specific syntax and may be less readable than other approaches.
* **New Array**:
	+ Pros: Simple and concise implementation using the spread operator (`...`). Can be efficient for large arrays.
	+ Cons: May not be as efficient as `push` followed by spread for small arrays.

**Library Usage**

None of the provided test cases use any external libraries. The benchmark relies solely on built-in JavaScript features.

**Special JS Feature/Syntax**

The benchmark uses the following special JS feature:

* **Spread Operator (`...`)**: This is a relatively recent addition to JavaScript, introduced in ECMAScript 2015 (ES6). It allows for concise array concatenation and other operations.
* **Rest Parameters**: Although not explicitly used in this benchmark, rest parameters (`...`) are also a feature of ES6.

**Other Alternatives**

If you want to test alternative approaches to array concatenation or spreading in JavaScript, you could consider the following:

1. Using `concat()`: This is another way to concatenate arrays using a method call.
2. Using `Array.prototype.reduce()`: This can be used to concatenate arrays by accumulating the elements into an accumulator array.
3. Using `array.map()` and `array.concat()`: Another approach is to use `map()` to create a new array with concatenated elements, followed by `concat()` to combine the results.

Keep in mind that each of these alternatives may have different performance characteristics and trade-offs compared to the original benchmark options.

Related benchmarks:

push-spread or splice performance (version: 0)

Comparing performance of: push-spread vs splice vs new array

Created: 4 years ago by: Guest

Jump to the latest result

push-spread

splice

new array

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):