Benchmark: array push vs length, to insert elements

Script Preparation code:

var arr = ['2', '2', '3', '2', '1', '[', '9', '8', '3', '0', 'p', 'g', 'r', 'p', 'u', 'h', ',', 'r', 'c', 'u', 'b', 'k', ']'];

Tests:

push
let a = []; for(let i = 0; i < arr.length; i ++){a[a.length] = arr.pop();}
length
let a = []; for(let i = 0; i < arr.length; i ++){a.push(arr.pop());}

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
push
length

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/131.0.0.0 Safari/537.36

Browser/OS: Chrome 131 on Mac OS X 10.15.7

View result in a separate tab

Test name	Executions per second
push	103263384.0 Ops/sec
length	104971592.0 Ops/sec

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

LLMs can make mistakes. Check important info.

Let's dive into the Benchmark Definition and test cases.

**Benchmark Purpose:**
The benchmark is designed to compare two approaches for inserting elements into an array in JavaScript:

1. Using `length` property to access the current length of the array, and then using the `push` method to insert a new element.
2. Using the `pop` method to remove the last element from the array, and then pushing it back onto the end.

**Comparison of Options:**
The benchmark is comparing two options:

1. **Using `length` property**: This approach checks if the current length of the array is accessible, and if so, uses it to insert a new element using the `push` method.
2. **Using `pop` method**: This approach removes the last element from the array using the `pop` method, and then pushes it back onto the end using the `push` method.

**Pros and Cons:**

* Using `length` property:
	+ Pros:
		- Can be faster since it avoids the overhead of the `pop` method.
	+ Cons:
		- May not work correctly if the array is very large or has a lot of elements, as this can cause performance issues with the `push` method.
* Using `pop` method:
	+ Pros:
		- Works correctly for all arrays, regardless of size.
	+ Cons:
		- Can be slower due to the overhead of the `pop` and `push` methods.

**Library:**
There is no library used in this benchmark.

**Special JS Feature or Syntax:**
The test cases use a special syntax in JavaScript called "array literal" (e.g. `let a = [];`). This syntax creates an array with the given values, but does not execute any code until the array is accessed.

Other Alternatives:
If you're interested in exploring alternative approaches, here are a few options:

1. Using `unshift` method: Instead of using `push`, you can use the `unshift` method to insert elements at the beginning of the array.
2. Using `splice` method: You can use the `splice` method to remove and replace elements in the array, which may be faster than using `push`.
3. Using a custom implementation: Depending on your specific requirements, you might consider implementing a custom algorithm for inserting elements into an array.

Keep in mind that the performance of these alternatives may vary depending on the specific use case and JavaScript engine being used.

Related benchmarks:

array push vs length, to insert elements (version: 0)

Comparing performance of: push vs length

Created: 4 years ago by: Guest

Jump to the latest result

push

length

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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