Benchmark: Shift vs spread - MeasureThat.net

Script Preparation code:

var loopShift = (arr) => {
    const _ = arr.shift();
    return arr.length ? loopShift(arr) : arr;
};

var loopSpread = ([_, ...arr]) => {
    return arr.length ? loopSpread(arr) : arr;
};

var arr = [1, 2, 3, 4];

Tests:

Shift
var t1 = loopShift(arr);
Spread
var t2 = loopSpread(arr);

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Shift
Spread

Fastest: N/A

Slowest: N/A

Latest run results:

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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.

**Benchmark Overview**

The provided benchmark compares two approaches to remove elements from an array: using `shift()` (known as "Shift") and using the spread operator (`...`) (known as "Spread").

**What are we testing?**

We're testing how fast each approach can remove elements from an array. In this case, the array contains four elements.

**Options compared**

Two options are being compared:

1. **Shift**: This approach uses the `shift()` method to remove elements from the beginning of the array. Each time a call is made to `shift()`, it returns the first element of the array and removes it from the array.
2. **Spread**: This approach uses the spread operator (`...`) to create a new array with the elements of the original array, excluding the first one.

**Pros and Cons**

* **Shift**:
	+ Pros: Simple, well-established method that's widely supported by browsers.
	+ Cons: Can be slower than Spread for large arrays, as it involves multiple function calls and returns values.
* **Spread**:
	+ Pros: More modern and efficient approach, especially for large arrays. It avoids the need to call `shift()` multiple times.
	+ Cons: Requires JavaScript 13 or later (due to the spread operator), which might not be supported by all browsers.

**Library usage**

There is no explicit library mentioned in the benchmark definition or test cases. However, the use of the spread operator (`...`) relies on modern JavaScript syntax and features introduced in ECMAScript 2018 (ES2018).

**Special JS feature or syntax**

The spread operator (`...`) was introduced in ECMAScript 2015 (ES2015) as a reserved word `SpreadElement`. It's used to create a new array with elements from an existing array. The usage of Spread in the benchmark is compatible with ES2015 and later versions.

**Alternatives**

Other alternatives to compare would be:

* Using `splice()` instead of `shift()`
* Using `slice()` instead of the spread operator
* Implementing a custom implementation for both Shift and Spread approaches

Keep in mind that these alternatives might affect the benchmark results, as they have different performance characteristics.

For more information about JavaScript benchmarks and microbenchmarks, I recommend checking out MeasureThat.net's documentation and resources.

Related benchmarks:

Shift vs spread (version: 0)

Comparing performance of: Shift vs Spread

Created: 4 years ago by: Guest

Jump to the latest result

Shift

Spread

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):