Benchmark: slice VS splice VS shift for fixed size list of objects v2

Script Preparation code:

var list = [];
for (let i = 0; i < 1000; i++) {
  list.push({'s':'usd', 'p':i});
}

Tests:

slice
list.push({'s':'cad', 'p':13}) list.push({'s':'cad', 'p':14}) list.push({'s':'cad', 'p':15}) list=list.slice(list.length-1000)
splice
list.push({'s':'cad', 'p':13}) list.push({'s':'cad', 'p':14}) list.push({'s':'cad', 'p':15}) list.splice(0, list.length-1000);
shift -while
list.push({'s':'cad', 'p':13}) list.push({'s':'cad', 'p':14}) list.push({'s':'cad', 'p':15}) while(list.length>1000){ list.shift(); }
shift-for
list.push({'s':'cad', 'p':13}) list.push({'s':'cad', 'p':14}) list.push({'s':'cad', 'p':15}) for(let i=0; i<(list.length-998); i++){ list.shift(); }

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
slice
splice
shift -while
shift-for

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 provided benchmark and explain what's being tested.

**Benchmark Overview**

The benchmark measures the performance of three different approaches to remove elements from an array in JavaScript:

1. `slice()`
2. `splice()`
3. `shift()` (with two variations: a while loop and a for loop)

**Test Case Explanation**

Each test case is defined by a "Benchmark Definition" string, which describes the specific operation being performed on the list. In this case, all tests create a fixed-size list of 1000 objects with properties 's' and 'p', then perform the specified removal operation.

The differences between the tests are:

* `slice()`: uses the `slice()` method to remove the last 1000 elements from the array.
* `splice()`: uses the `splice()` method to remove the first 1000 elements from the array.
* `shift - while`: uses a while loop to shift elements from the end of the array until there are 1000 elements left.
* `shift-for`: uses a for loop to shift elements from the end of the array until there are 1000 elements left.

**Library Used**

In all tests, the JavaScript built-in `Array` methods are used without any external libraries. However, it's worth noting that some browsers may have additional polyfills or implementations of these methods that might affect performance.

**Special JS Feature/Syntax**

None of the tests explicitly use special JavaScript features or syntax like async/await, arrow functions, or template literals. The focus is on the fundamental operations of array manipulation in JavaScript.

**Options Compared**

The main options being compared are:

* Removal strategy: `slice()`, `splice()`, `shift - while`, and `shift-for`. Each approach has its own trade-offs:
	+ `slice()` is often faster because it creates a new array without modifying the original, but it may incur additional memory overhead.
	+ `splice()` modifies the original array and can be slower due to the cost of reallocations. However, it's also more flexible and can remove elements from any position in the array.
	+ `shift - while` is similar to `slice()`, but uses a loop instead of creating a new array. This approach can be faster for very large arrays because it avoids memory allocation, but it may be slower due to the overhead of the loop.
	+ `shift-for` is similar to `shift - while`, but uses a traditional for loop instead of a while loop. This approach can be faster and more readable than the while loop version, but it may incur additional overhead due to the loop.

**Pros and Cons**

* `slice()`: Pros: fast, efficient; Cons: creates a new array, may incur memory overhead.
* `splice()`: Pros: flexible, can remove elements from any position in the array; Cons: slower due to reallocation costs.
* `shift - while` and `shift-for`: Pros: potentially faster than `slice()` or `splice()`, avoid memory allocation; Cons: may be slower due to loop overhead.

**Other Alternatives**

If you need to remove elements from an array in JavaScript, consider the following alternatives:

* Using `filter()` instead of `shift - while` or `shift-for`. While this approach is not as efficient for removing a fixed number of elements, it can be faster for removing all elements that meet a certain condition.
* Using a library like Lodash's `tail()` method, which removes the first `n` elements from an array without modifying the original.

Keep in mind that these alternatives may incur different overheads or trade-offs depending on your specific use case.

Related benchmarks:

slice VS splice VS shift for fixed size list of objects v2 (version: 0)

Comparing performance of: slice vs splice vs shift -while vs shift-for

Created: 5 years ago by: Guest

Jump to the latest result

slice

splice

shift -while

shift-for

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):