Benchmark: Array slice vs shift (2)

Script Preparation code:

var arr = Array.from(new Array(100), (val, idx) => idx);

Tests:

slice
arr.slice(1);
shift
arr.shift();

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
slice
shift

Fastest: N/A

Slowest: N/A

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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 its test cases.

**Benchmark Overview**

The benchmark measures the performance of two approaches to remove elements from an array: `arr.slice(1)` and `arr.shift()`. The array is created using `Array.from(new Array(100), (val, idx) => idx);`, which generates a new array with 100 elements, each initialized with its index.

**Library Used**

In the script preparation code, `Array.from` is used to create the array. `Array.from()` is a modern JavaScript method that creates a new array from an iterable or an array-like object. Its purpose is to provide a way to convert other data structures into arrays.

**Special JS Feature/ Syntax**

The benchmark uses two special features:

*   Array methods (`slice` and `shift`) are used, which are part of the ECMAScript standard (ES6) and are supported in most modern browsers.
*   The `(val, idx) => idx` syntax is a shorthand way to create an anonymous function. This syntax is also part of ES6.

**Options Compared**

The two options being compared are:

1.  `arr.slice(1)`
2.  `arr.shift()`

Both methods remove elements from the array, but they operate on different parts of the array.

*   `slice` returns a new array containing all elements except the first one (`arr.slice(1)`). This method modifies the original array.
*   `shift` removes and returns the first element from the array. The returned value is the removed element, and the array is modified in place.

**Pros and Cons of Each Approach**

Here are some pros and cons of each approach:

*   `arr.slice(1)`:
    *   Pros:
        +   Efficient for creating a new array with a subset of elements.
        +   Does not modify the original array.
    *   Cons:
        +   Creates a new array, which can be memory-intensive.
        +   May have overhead due to the creation of a new array object.
*   `arr.shift()`:
    *   Pros:
        +   Efficient for modifying an existing array by removing elements.
        +   Does not create a new array object.
    *   Cons:
        +   Returns the removed element, which can be lost if not stored elsewhere.
        +   May have slower performance due to the overhead of removing elements.

**Other Considerations**

When choosing between `slice` and `shift`, consider the specific use case:

*   Use `arr.slice(1)` when you need to create a new array with a subset of elements, and it's essential to preserve the original array.
*   Use `arr.shift()` when you're modifying an existing array by removing elements and don't need the removed value.

**Alternatives**

Other alternatives to `slice` and `shift` include:

*   Using ` splice()`: Removes elements from the array at a specified index and returns the removed elements. Like `slice`, it modifies the original array.
*   Using `pop()` or `unshift()`: Removes elements from the end (using `pop`) or beginning (using `unshift`) of the array, respectively.
*   Creating an intermediate array using `map()`, `reduce()`, and indexing to achieve the same result as `slice()`.

Keep in mind that each approach has its own trade-offs and may be more suitable depending on your specific use case.

Related benchmarks:

Array slice vs shift (2) (version: 0)

Comparing performance of: slice vs shift

Created: 2 years ago by: Guest

Jump to the latest result

slice

shift

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):