Benchmark: slice vs destruction with inserts

Script Preparation code:

var list = [];
for (var i = 0; i < 1000 * 1000; i++) {
  list.push(i);
}

Tests:

slice
let foo = list.slice() foo.unshift(1); return foo;
destruction
return [1, ...list];

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
slice
destruction

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 break down the benchmark and explain what's being tested.

**Benchmark Definition**

The benchmark is comparing two approaches to create an array slice of a large list: `slice` and destruction with inserts (`destruction`).

**Options Compared**

* **Slice**: The `slice` method creates a new array by copying a subset of elements from the original array.
* **Destruction with Inserts**: This approach modifies the original array by adding elements at the beginning using the `unshift()` method.

**Pros and Cons**

* **Slice**:
	+ Pros: Efficient, does not modify the original array, and is generally faster for large arrays.
	+ Cons: Creates a new array object, which can lead to memory allocation overhead.
* **Destruction with Inserts**:
	+ Pros: Does not create a new array object, which can be beneficial for memory-constrained environments or performance-critical code.
	+ Cons: Modifies the original array, which may affect other parts of the code that rely on the unchanged array.

**Library and Purpose**

There is no explicit library mentioned in the benchmark definition. However, it's likely that the `Array.prototype.slice()` method is being used, which is a built-in JavaScript method for creating an array slice.

**Special JS Feature or Syntax**

There are no special JavaScript features or syntaxes explicitly mentioned in this benchmark. However, note that using `...` (the spread operator) to create a new array from an existing one is a relatively recent feature introduced in ECMAScript 2015.

**Other Considerations**

When deciding between these two approaches, consider the following:

* **Memory constraints**: If memory allocation is a concern, destruction with inserts might be a better choice.
* **Performance-critical code**: Slice is generally faster and more efficient for large arrays.
* **Code readability and maintainability**: Using destruction with inserts can make the code more complex to read and understand.

**Alternatives**

Other alternatives for creating an array slice or modifying an existing array include:

* `Array.prototype.concat()` (although slower than `slice` due to its overhead)
* `array.map()` followed by `array.slice()` (though less efficient than using `slice` directly)
* Using a library like Lodash, which provides alternative methods for array manipulation.

Keep in mind that the performance differences between these approaches are usually negligible unless you're dealing with extremely large arrays or performance-critical code.

Related benchmarks:

slice vs destruction with inserts (version: 0)

Comparing performance of: slice vs destruction

Created: 4 years ago by: Guest

Jump to the latest result

slice

destruction

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):