Benchmark: push vs direct assign

Tests:

push
const arr = []; for (let i = 0; i < 10; i++) { arr.push(i); }
direct assign
const arr = []; for (let i = 0; i < 10; i++) { arr[arr.length] = i; }

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
push
direct assign

Fastest: N/A

Slowest: N/A

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

LLMs can make mistakes. Check important info.

Let's break down the provided benchmark and explain what is being tested, compared, and the pros/cons of different approaches.

**Benchmark Purpose:**
The goal of this benchmark is to compare the performance of two ways to add elements to an array in JavaScript:

1. **`arr.push(i)`**: Using the `push()` method to add an element to the end of the array.
2. **`arr[arr.length] = i`**: Directly assigning a value to the index at the current length of the array.

**Comparison:**
The benchmark is comparing the execution time of both approaches for adding 10 elements to an empty array.

**Pros and Cons:**

* `push()` method:
	+ Pros:
		- More concise and readable code.
		- Easier to understand the intent of adding an element to the end of the array.
	+ Cons:
		- May have overhead due to searching for the last index or using a heap, depending on the implementation.
* `arr[arr.length] = i`:
	+ Pros:
		- Direct access to the last index can be faster in some cases (e.g., when the array is very large).
	+ Cons:
		- Less readable code and more prone to errors (e.g., incorrect indexing).

**Library/Functionality:**
There is no specific library or functionality being tested here. The benchmark only involves basic JavaScript operations.

**Special JS Features/Syntax:**
There are no special JavaScript features or syntax used in this benchmark.

**Benchmark Preparation Code:**
The preparation code is empty, which means the benchmark starts with an empty array and nothing else is done before executing the test case.

**Alternatives:**
Other alternatives to compare might include:

* Using `arr.splice()` instead of `push()`
* Using `arr.slice().push(i)` instead of `push()`
* Using a different data structure, such as a linked list or a typed array
* Adding additional elements to the array before testing

Keep in mind that the choice of alternative will depend on the specific requirements and use cases being compared.

As for test users' special JS features or syntax, it's worth noting that this benchmark doesn't include any modern JavaScript features like async/await, promises, or arrow functions. If you wanted to add these, you would need to modify the `Benchmark Definition` json and the test cases accordingly.

Latest run results:

Run details: (Test run date: 4 years ago)

User agent: Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/79.0.3945.130 Safari/537.36

Browser/OS: Chrome 79 on Linux

View result in a separate tab

Test name	Executions per second
push	13886246.0 Ops/sec
direct assign	13617415.0 Ops/sec

Related benchmarks:

push vs direct assign (version: 1)

Comparing performance of: push vs direct assign

Created: 4 years ago by: Registered User

Jump to the latest result

push

direct assign

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):