Benchmark: String concatenation vs array join (with single push before)

Script Preparation code:

var str = "";
var i;
var sArr = [];

Tests:

String concatentation
for (i = 1000; i > 0; i--) { str += "String concatenation. "; }
Array join (with single push before)
sArr.push("String concatenation. "); for (i = 1000; i > 0; i--) { sArr[i] = "String concatenation. "; } str = sArr.join("");
Array join (w/ push)
for (i = 1000; i > 0; i--) { sArr[i] = "String concatenation. "; } str = sArr.join("");

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

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

Fastest: N/A

Slowest: N/A

Latest run results:

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

User agent: Mozilla/5.0 (Linux; Android 10; SM-A505FN) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/86.0.4240.198 Mobile Safari/537.36

Browser/OS: Chrome Mobile 86 on Android

View result in a separate tab

Test name	Executions per second
String concatentation	1283.4 Ops/sec
Array join (with single push before)	1224.4 Ops/sec
Array join (w/ push)	704.8 Ops/sec

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

LLMs can make mistakes. Check important info.

Let's break down the provided JSON and explain what is tested, the compared options, their pros and cons, and other considerations.

**Benchmark Definition**

The benchmark measures the performance of two approaches for string concatenation: using the `+` operator (string concatenation) versus using the `join()` method with an array (array join). The benchmark consists of three test cases:

1. **String Concatenation**: This approach uses the `+` operator to concatenate a string to a variable `str`.
2. **Array Join (with single push before)**: This approach creates an array, pushes a string onto it, and then uses the `join()` method to concatenate all elements of the array into a single string.
3. **Array Join (w/ push)**: This approach is similar to the previous one, but without the single push before.

**Options Compared**

The benchmark compares two approaches:

1. **String Concatenation**: using the `+` operator
2. **Array Join**: using the `join()` method with an array

**Pros and Cons of Each Approach**

1. **String Concatenation**:
	* Pros: simple, easy to understand, and implement.
	* Cons: can be slow for large numbers of concatenations due to the overhead of creating a new string object on each operation.
2. **Array Join**:
	* Pros: efficient for large arrays since it avoids the overhead of creating a new string object on each concatenation.
	* Cons: requires more memory and processing power compared to string concatenation, as it needs to store all elements in an array.

**Library Used**

The benchmark uses none, but it's worth noting that if you were to use libraries like Lodash or Underscore.js, they might provide optimized implementations of these operations.

**Special JS Feature/Syntax**

There is no special JavaScript feature or syntax used in this benchmark. The focus is on the performance comparison between two basic string concatenation approaches.

**Other Considerations**

When writing benchmarks like this one, it's essential to consider factors such as:

* **Warm-up and cold-start effects**: Some operations might take time to warm up or have a cold start due to initialization costs. In this case, the benchmark is likely designed to minimize these effects by repeating each test multiple times.
* **Memory allocation and deallocation**: The benchmark should account for memory allocation and deallocation overheads, as it can impact performance.

**Alternatives**

If you were to write similar benchmarks, you might consider using alternative approaches or variations, such as:

* Using different string concatenation methods (e.g., `StringBuilder` in JavaScript)
* Comparing the performance of other array join libraries or implementations
* Adding more test cases with varying input sizes and scenarios

Keep in mind that benchmarking is an iterative process, and you may need to revisit and refine your approach as you gather more data and insights.

Related benchmarks:

String concatenation vs array join (with single push before) (version: 0)

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

Created: 4 years ago by: Guest

Jump to the latest result

String concatentation

Array join (with single push before)

Array join (w/ push)

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

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