Benchmark: JS String '+' short v.s. long strings 2

Script Preparation code:

var nLoops = 1000;
var shortString = String(Math.random());
var longString = '';

for (var i = 0; i < 40; i++) {
  longString += String(Math.random());
}

Tests:

Add short string each loop
var str = ''; for (var i = 0; i < nLoops; i++) { str += shortString; }
Add long string each loop
var str = ''; for (var i = 0; i < nLoops; i++) { str += longString; }

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Add short string each loop
Add long string each loop

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:109.0) Gecko/20100101 Firefox/109.0

Browser/OS: Firefox 109 on Mac OS X 10.15

View result in a separate tab

Test name	Executions per second
Add short string each loop	363201.4 Ops/sec
Add long string each loop	361800.6 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 test cases.

**Benchmark Definition**

The provided JSON represents a JavaScript microbenchmark that tests the performance of concatenating strings in two different ways: using short strings versus long strings.

**Options Compared**

There are two main options being compared:

1. **Short Strings**: The code uses `String(Math.random())` to generate a random short string, which is repeated 40 times in a loop.
2. **Long Strings**: The code generates a long string by concatenating 40 instances of `String(Math.random())`, repeating it in a loop.

**Pros and Cons**

* Using short strings:
	+ Pros: Short strings are likely to be more efficient due to the overhead of creating longer strings.
	+ Cons: The performance difference might not be significant, as JavaScript's string concatenation is optimized for performance.
* Using long strings:
	+ Pros: Long strings can help reduce the number of allocations and copies required by the engine.
	+ Cons: Long strings are likely to be slower due to the overhead of creating longer strings.

**Library Used**

None explicitly mentioned in this benchmark. However, JavaScript's built-in `String` constructor is used for both short and long strings.

**Special JS Feature or Syntax**

There isn't any special feature or syntax being tested in this benchmark. It's a straightforward string concatenation test.

**Benchmark Preparation Code**

The preparation code initializes variables:

* `nLoops`: The number of loops to perform, set to 1000.
* `shortString` and `longString`: Variables that store the short and long strings, respectively.

**Individual Test Cases**

There are two test cases:

1. **"Add short string each loop"**: This test case concatenates the short string to an empty string (`''`) in a loop.
2. **"Add long string each loop"**: This test case concatenates the long string to an empty string (`''`) in a loop.

**Latest Benchmark Result**

The benchmark result shows the execution count per second for both test cases:

* "Add short string each loop": 363,201 executions per second
* "Add long string each loop": 361,800 executions per second

This suggests that using short strings results in slightly better performance.

**Other Alternatives**

If you're interested in exploring alternative approaches, here are a few options:

1. **Use a library like `lodash`**: Lodash provides an efficient way to concatenate strings using the `concat` function or the `_str` helper.
2. **Use a custom allocation strategy**: Implementing a custom string allocation strategy might provide better performance by reducing memory allocations and copies.
3. **Test with different loop sizes**: Experimenting with varying loop sizes can help determine the optimal size for maximum performance.

Keep in mind that these alternatives may require additional setup, testing, and optimization to ensure they provide significant performance gains.

Related benchmarks:

JS String '+' short v.s. long strings 2 (version: 0)

Does the size of the string concatenated affect the performance?

Comparing performance of: Add short string each loop vs Add long string each loop

Created: 2 years ago by: Guest

Jump to the latest result

Add short string each loop

Add long string each loop

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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