Benchmark: String concatenation vs array join #2

Tests:

String concatentation
let str = ""; for (let i = 0; i < 1000; i++) { str += "String concatenation. "; }
Array join
let arr = []; for (let i = 0; i < 1000; i++) { arr[i] = "String concatenation. "; } str = arr.join("");
Array join (w/ push)
let arr = []; for (let i = 0; i < 1000; i++) { arr.push("String concatenation. "); } str = arr.join("");

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
String concatentation
Array join
Array join (w/ push)

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 28 days ago)

User agent: Mozilla/5.0 (Linux; arm_64; Android 16; CPH2653) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/146.0.7680.101 YaBrowser/26.4.2.101.00 Mobile Safari/537.36

Browser/OS: Yandex Browser 26 on Android

View result in a separate tab

Test name	Executions per second
String concatentation	534244.8 Ops/sec
Array join	82576.0 Ops/sec
Array join (w/ push)	70081.8 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 provided benchmark and explain what's being tested.

**Benchmark Overview**

The benchmark is testing two approaches for string concatenation in JavaScript:

1. **String Concatenation**: Directly appending strings to a variable using the `+` operator or string interpolation (`"Hello, " + name`).
2. **Array Join**: Using the `join()` method on an array of strings.

**Options Compared**

The benchmark is comparing three variations of array join:

1. **Array Join (w/ push)**: Creating an empty array and pushing elements onto it before joining using the `push()` method.
2. **Array Join**: Creating an empty array and then joining its elements using the `join()` method.

**Pros and Cons**

* **String Concatenation**:
	+ Pros: Simple, widely supported, and easy to read.
	+ Cons: Can lead to performance issues due to the creation of temporary strings and the overhead of string concatenation.
* **Array Join (w/ push)**:
	+ Pros: Can be faster than traditional array join for large arrays because it avoids creating intermediate strings.
	+ Cons: Requires more memory allocation and can lead to slower performance for small arrays.
* **Array Join**:
	+ Pros: More efficient than traditional array join for large arrays, as it avoids creating intermediate strings.
	+ Cons: Can be slower than `push()`-based approach for small arrays.

**Special JS Feature**

None mentioned in this benchmark.

**Library and Purpose**

The `join()` method is a built-in JavaScript method that concatenates all elements of an array into a single string. The purpose is to provide a convenient way to concatenate strings in arrays without having to use the `+` operator or string interpolation.

**Other Alternatives**

For larger projects, you might want to consider using libraries like [Lodash](https://lodash.com/) which provides a more efficient and concise way of concatenating arrays using its `join()` function.

Keep in mind that the performance differences between these approaches are generally significant only for large datasets or performance-critical code. For smaller projects, readability and simplicity might be more important considerations than micro-optimizations.

In this benchmark, the goal is likely to demonstrate the performance difference between these three methods, which can help developers make informed decisions about their coding practices.

Related benchmarks:

String concatenation vs array join #2 (version: 0)

Comparing performance of: String concatentation vs Array join vs Array join (w/ push)

Created: 5 years ago by: Guest

Jump to the latest result

String concatentation

Array join

Array join (w/ push)

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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