Benchmark: push vs index - MeasureThat.net

Script Preparation code:

var times = 1000;

var arr = [];

Tests:

push
arr = []; for (var i = 0; i < times; i++) { arr.push(1337); }
index
arr = []; for (var i = 0; i < times; i++) { arr[i] = 1337; }
index insert at last position
arr = []; for (var i = 0; i < times; i++) { arr[arr.length] = 1337; }

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
push
index
index insert at last position

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 6 months ago)

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:146.0) Gecko/20100101 Firefox/146.0

Browser/OS: Firefox 146 on Windows

View result in a separate tab

Test name	Executions per second
push	630760.9 Ops/sec
index	402274.0 Ops/sec
index insert at last position	380372.2 Ops/sec

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

LLMs can make mistakes. Check important info.

Let's break down the benchmark and its components.

**Benchmark Description**

The benchmark compares three different approaches to append an item to an array in JavaScript:

1. `push`
2. Index-based assignment (`arr[i] = 1337`)
3. Insertion at the last position of the array (`arr[arr.length] = 1337`)

These approaches are used to measure their performance, and the results will help determine which method is faster.

**Options Compared**

The three options compared in this benchmark are:

* `push`: This is a built-in JavaScript method that appends an item to the end of an array.
* Index-based assignment: This involves accessing the array using its index and assigning a value to it. In this case, the index is set to 0 and incremented for each iteration.
* Insertion at the last position: Similar to index-based assignment, but instead of accessing the array by index, we're using the `length` property to get the current length of the array and appending to it.

**Pros and Cons**

Here's a brief overview of the pros and cons of each approach:

* **push**: This is a built-in method that's optimized for performance. It's also a simple and concise way to append an item to an array.
	+ Pros: Fast, easy to use, built-in method
	+ Cons: May not be as efficient if used in a loop or with large arrays
* **Index-based assignment**: This approach requires manual index management, which can lead to bugs and errors if not done correctly. However, it can also provide more control over the array's internal state.
	+ Pros: More control over array manipulation, potential performance benefits for specific use cases
	+ Cons: Requires manual indexing, error-prone, less intuitive for many developers
* **Insertion at the last position**: This approach is similar to index-based assignment but uses the `length` property to access the end of the array. It's also relatively simple and easy to understand.
	+ Pros: Simple and easy to use, similar performance characteristics to `push`
	+ Cons: May not be as efficient for large arrays or complex iterations

**Library Usage**

There is no library explicitly mentioned in this benchmark definition.

**Special JS Features/Syntax**

None of the approaches in this benchmark rely on special JavaScript features or syntax. They are all standard, widely-supported methods.

**Other Alternatives**

If you're interested in exploring alternative approaches to appending items to an array, here are a few options:

* Using `unshift()` instead of `push()`: This method appends an item to the beginning of the array.
* Using `splice()` with negative indices: You can use negative indices to remove or insert items at specific positions within the array.
* Using a library like Lodash's `compact` function: This function can be used to append items to an array in a more functional programming style.

Keep in mind that these alternatives may have different performance characteristics, complexity levels, and use cases compared to the methods presented in this benchmark.

Related benchmarks:

push vs index (version: 2)

array methods to append an item

Comparing performance of: push vs index vs index insert at last position

Created: 9 years ago by: Registered User

Jump to the latest result

push

index

index insert at last position

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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