Benchmark: Spread assign vs Array push

Tests:

add item via Push
let arr = [ { id: 1, title: "Todo One", completed: false }, { id: 2, title: "Todo Two", completed: true }, { id: 3, title: "Todo Three", completed: false } ]; let newTodo = { id: 4, title: "Todo Four", completed: false }; arr.push(newTodo)
add item via Spread and destructing
let arr = [ { id: 1, title: "Todo One", completed: false }, { id: 2, title: "Todo Two", completed: true }, { id: 3, title: "Todo Three", completed: false } ]; let newTodo = { id: 4, title: "Todo Four", completed: false }; arr = [...arr, newTodo];

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
add item via Push
add item via Spread and destructing

Fastest: N/A

Slowest: N/A

Latest run results:

No previous run results

This benchmark does not have any results yet. Be the first one to run it!

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

LLMs can make mistakes. Check important info.

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

**Benchmark Overview**

The benchmark is comparing two approaches to add an item to an array in JavaScript: using `arr.push()` versus using the spread operator (`[...arr, newTodo]`).

**Options Compared**

* **Approach 1: Using `arr.push()`
	+ This approach involves appending a new object to the end of the array using the `push()` method.
	+ The `push()` method modifies the original array and returns the new length of the array.
* **Approach 2: Using spread operator (`[...arr, newTodo]`)
	+ This approach creates a new array by spreading the original array and appending the new object to it.
	+ The resulting array is created without modifying the original array.

**Pros and Cons of Each Approach**

* **Using `arr.push()`:**
	+ Pros:
		- Often faster since it only requires updating the length of the array.
		- Can be more efficient for large arrays, as it avoids creating a new array.
	+ Cons:
		- May lead to unnecessary changes in the original array if the caller is not expecting this behavior.
		- Can result in slower performance if the array is very large and needs to be traversed multiple times.
* **Using spread operator (`[...arr, newTodo]`):**
	+ Pros:
		- Creates a new array without modifying the original array.
		- Often more readable and maintainable code.
	+ Cons:
		- Can result in slower performance due to the creation of a new array.
		- May be less efficient for very large arrays, as it requires allocating additional memory.

**Library Used**

The benchmark does not explicitly mention any libraries being used. However, it's worth noting that some JavaScript engines or browsers might provide built-in optimizations or assumptions about how arrays should be modified. These optimizations can affect the performance of the `push()` method.

**Special JS Feature or Syntax**

The benchmark uses the spread operator (`[...arr, newTodo]`), which is a relatively recent feature in JavaScript introduced in ECMAScript 2018 (ES2018). This syntax allows for more concise and expressive code when working with arrays. The benchmark also uses the `let` declaration and template literals (e.g., `\r\n\t{\r\n...\r\n}\r\n`) which are part of modern JavaScript syntax.

**Other Alternatives**

There are other ways to add an item to an array, such as:

* Using `concat()`: `arr.concat([newTodo])`
* Using `unshift()`: `arr.unshift(newTodo)`
* Using a custom implementation, such as creating a new array and then assigning it back to the original array.

However, these alternatives are not compared in this benchmark.

Related benchmarks:

Spread assign vs Array push (version: 0)

Comparing performance of: add item via Push vs add item via Spread and destructing

Created: 6 years ago by: Guest

Jump to the latest result

add item via Push

add item via Spread and destructing

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):