Benchmark: Array.prototype.slice vs spread operator on objects

Tests:

Array.prototype.slice
var params = [ { "code": "u2", "name": "Company A", "logoUrl": "https://cdn.example.com/logos/1.png", "duration": 105 }, { "code": "blablacarbus", "name": "Company B", "logoUrl": "https://cdn.example.com/logos/2.png", "duration": 130 }, { "code": "xyz", "name": "Company C", "logoUrl": "https://cdn.example.com/logos/3.png", "duration": 90 }, { "code": "pqr", "name": "Company D", "logoUrl": "https://cdn.example.com/logos/4.png", "duration": 175 }, { "code": "abc", "name": "Company E", "logoUrl": "https://cdn.example.com/logos/5.png", "duration": 200 } ]; var other = params.slice();
spread operator
var params = [ { "code": "u2", "name": "Company A", "logoUrl": "https://cdn.example.com/logos/1.png", "duration": 105 }, { "code": "blablacarbus", "name": "Company B", "logoUrl": "https://cdn.example.com/logos/2.png", "duration": 130 }, { "code": "xyz", "name": "Company C", "logoUrl": "https://cdn.example.com/logos/3.png", "duration": 90 }, { "code": "pqr", "name": "Company D", "logoUrl": "https://cdn.example.com/logos/4.png", "duration": 175 }, { "code": "abc", "name": "Company E", "logoUrl": "https://cdn.example.com/logos/5.png", "duration": 200 } ] var other = [ ...params ]

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Array.prototype.slice
spread operator

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: one year ago)

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/116.0.0.0 Safari/537.36

Browser/OS: Chrome 116 on Mac OS X 10.15.7

View result in a separate tab

Test name	Executions per second
Array.prototype.slice	65695444.0 Ops/sec
spread operator	57724904.0 Ops/sec

Autogenerated LLM Summary (model llama3.2:3b, generated one month 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 create a shallow copy of an array in JavaScript:

1. `Array.prototype.slice()`
2. The spread operator (`[ ...params ]`)

**Options Compared**

The benchmark tests both methods on an array of objects, where each object has properties like `code`, `name`, `logoUrl`, and `duration`. The test creates a shallow copy of the original array using each method and measures the execution time.

**Pros and Cons of Each Approach**

### Array.prototype.slice()

* Pros:
	+ Widely supported and well-documented.
	+ Efficient for large arrays, as it only creates a new reference to the sliced portion of the array.
* Cons:
	+ Creates a shallow copy, which means that any nested objects or arrays are copied by reference. This can lead to unexpected behavior if the original data is modified elsewhere in the code.
	+ Can be slower than the spread operator for very large arrays.

### Spread Operator ([ ...params ])

* Pros:
	+ Creates a deep copy of the array, which means that any nested objects or arrays are fully cloned.
	+ Often faster and more memory-efficient than `Array.prototype.slice()` for very large arrays.
* Cons:
	+ Less widely supported and less well-documented compared to `Array.prototype.slice()`.
	+ May be slower than `Array.prototype.slice()` for smaller arrays.

**Library Used**

There is no specific library used in this benchmark. The spread operator (`[ ...params ]`) is a built-in JavaScript feature that allows creating a shallow copy of an array by spreading its elements into a new array.

**Special JS Feature or Syntax**

The spread operator (`[ ...params ]`) is a relatively recent addition to the JavaScript language, introduced in ECMAScript 2015 (ES6). It's designed to make working with arrays and objects more concise and expressive.

**Other Alternatives**

If you need to create a shallow copy of an array or object in JavaScript, other alternatives include:

* `Array.prototype.concat()`: Creates a new array by concatenating the original array with another array.
* `Object.assign()`: Creates a new object by copying properties from an existing object.
* Library functions like Lodash's `cloneDeep()` or Immutable.js's `Map` and `Set` utilities.

Keep in mind that each of these alternatives has its own trade-offs in terms of performance, memory usage, and compatibility with different versions of JavaScript.

Related benchmarks:

Array.prototype.slice vs spread operator on objects (version: 0)

Comparing performance of: Array.prototype.slice vs spread operator

Created: one year ago by: Guest

Jump to the latest result

Array.prototype.slice

spread operator

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated one month ago):