Benchmark: String concat vs array join

Tests:

String concat
var target = '' target += '1,' target += '2,' target += '3,' target += '4,' target += '5,' target += '6,' target += '7,' target += '8,' target += '9,' target += '10,' target += '11,' target += '12,' target += '13,' target += '14,' target += '15,' target += '16,' target += '17,' target += '18,' target += '19,' target += '20,'
Array join
var target = [] target.push('1') target.push('2') target.push('3') target.push('4') target.push('5') target.push('6') target.push('7') target.push('8') target.push('9') target.push('10') target.push('11') target.push('12') target.push('13') target.push('14') target.push('15') target.push('16') target.push('17') target.push('18') target.push('19') target.push('20') target.join(',')

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
String concat
Array join

Fastest: N/A

Slowest: N/A

Latest run results:

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

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:105.0) Gecko/20100101 Firefox/105.0

Browser/OS: Firefox 105 on Mac OS X 10.15

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Test name	Executions per second
String concat	193232064.0 Ops/sec
Array join	1240013.6 Ops/sec

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

LLMs can make mistakes. Check important info.

Let's dive into the explanation of what's being tested in this benchmark, the options compared, their pros and cons, and other considerations.

**What is being tested?**

The provided JSON represents a JavaScript microbenchmark that compares two approaches to concatenate strings: using the `+=` operator for string concatenation and generating an array with elements and joining them at the end using the `join()` method.

**Options compared**

There are two test cases:

1. **String concat**: This test case uses the `+=` operator to concatenate strings.
2. **Array join**: This test case generates an array with elements and joins them at the end using the `join()` method.

**Pros and cons of each approach:**

* **String concat (+=)**:
	+ Pros:
		- Simple and straightforward implementation.
		- Fast execution, as it avoids creating intermediate arrays or strings.
	+ Cons:
		- Can lead to slower performance for large numbers of concatenations, as it creates a new string object on each iteration.
		- May cause issues with memory management if not used carefully.
* **Array join**:
	+ Pros:
		- More flexible and scalable, as it can handle large arrays without significant performance degradation.
		- Avoids the creation of intermediate strings or objects, reducing memory usage.
	+ Cons:
		- Requires creating an array and then joining its elements, which may have overhead compared to simple concatenation.

**Other considerations:**

* **Library usage**: Neither test case uses any external libraries, making it a purely JavaScript-based comparison.
* **Special JS features or syntax**: There are no special JS features or syntax used in these test cases; they focus on the basic implementation of string concatenation and array join.

**Alternatives:**

Other alternatives for string concatenation include:

* Using `template literals` (e.g., `const result = '1' + '2' + '3';`): This approach is more concise but may have similar performance characteristics to `+=`.
* Utilizing `Array.prototype.map()` and `Array.prototype.join()`: Similar to the array join approach, this method creates an intermediate array and then joins its elements.

However, it's worth noting that these alternatives might not be as straightforward or easy to implement as the simple `+=` operator or the more complex array join approach.

Related benchmarks:

String concat vs array join (version: 0)

Checking the performance of several string concat or generating an array with the elements and joining them at the end.

Comparing performance of: String concat vs Array join

Created: 4 years ago by: Guest

Jump to the latest result

String concat

Array join

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):