Benchmark: string concat + join vs unshift + join (2)

Script Preparation code:

function case1() {
  var el = 'test';
  var arr = ['foo', 'bar'];

  return el + arr.join(',');
}

function case2() {
  var el = 'test';
  var arr = ['foo', 'bar'];

  arr.unshift(el);
  return arr.join(',');
}

Tests:

string concat + join
case1()
unshift + join
case2()

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
string concat + join
unshift + join

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 2 years ago)

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/123.0.0.0 Safari/537.36

Browser/OS: Chrome 123 on Windows

View result in a separate tab

Test name	Executions per second
string concat + join	10527602.0 Ops/sec
unshift + join	5708046.0 Ops/sec

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

LLMs can make mistakes. Check important info.

I'd be happy to explain the provided benchmark and its options.

**Benchmark Overview**

The given benchmark is for comparing two JavaScript methods: concatenating strings using the `+` operator followed by joining an array with a comma separator, and pushing an element onto an array and then joining it. The benchmark aims to determine which approach is faster in terms of executions per second.

**Script Preparation Code**

The script preparation code defines two functions:

1. `case1()`: Concatenates the string `'test'` with an array `arr` containing elements `'foo'` and `'bar'`, using the `+` operator followed by joining the array elements with a comma separator.
2. `case2()`: Pushes the string `'test'` onto the same array `arr`, and then joins its elements with a comma separator.

**Options Compared**

The benchmark compares two options:

1. **String Concatenation**: This approach uses the `+` operator to concatenate strings, followed by joining an array using the `join()` method.
2. **Array Manipulation**: This approach pushes an element onto an array and then joins its elements with a comma separator.

**Pros and Cons of Each Approach**

1. **String Concatenation**
	* Pros:
		+ Simple to implement
		+ Fast, since strings are immutable in JavaScript
	* Cons:
		+ Can be slow for large arrays, due to the creation of intermediate strings
2. **Array Manipulation**
	* Pros:
		+ May be faster for large arrays, as it avoids creating intermediate strings
	* Cons:
		+ Requires pushing an element onto the array first, which can be slower than concatenation

**Library Used**

None is explicitly mentioned in the provided code.

**Special JS Features or Syntax**

The benchmark uses JavaScript's built-in `join()` method and array operations (pushing elements onto an array). No special features or syntax are used beyond standard JavaScript.

**Other Considerations**

When evaluating these approaches, consider the following:

* String concatenation can lead to performance issues when dealing with large arrays, as it creates intermediate strings.
* Array manipulation can be slower than concatenation for small arrays, but may provide better performance for larger datasets.
* The benchmark's results will depend on factors like array size, JavaScript engine, and hardware.

**Alternatives**

If you're interested in exploring alternative approaches or variations of these methods, consider the following:

* Using `StringBuilder`-like libraries (e.g., `string-pool`) to optimize string concatenation
* Implementing a custom array manipulation function with potentially better performance
* Using different joining characters or separators for improved performance
* Evaluating other JavaScript methods, such as using `Array.prototype.reduce()` or `Array.prototype.forEach()`, for joining arrays.

Related benchmarks:

string concat + join vs unshift + join (2) (version: 0)

Comparing performance of: string concat + join vs unshift + join

Created: 2 years ago by: Guest

Jump to the latest result

string concat + join

unshift + join

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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