Benchmark: String Concatenation with a predefined String Array set

Script Preparation code:

var arr = Array(100).fill('A');
var str = "";

Tests:

concat (w/ spread operator)
str.concat(...arr);
concat using for loop
for(let i=0; i<100; i++){ str.concat(arr[i]); }

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
concat (w/ spread operator)
concat using for 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_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/121.0.0.0 Safari/537.36

Browser/OS: Chrome 121 on Mac OS X 10.15.7

View result in a separate tab

Test name	Executions per second
concat (w/ spread operator)	2484601.5 Ops/sec
concat using for loop	179278.5 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 JSON and explain what is being tested, the options compared, and their pros and cons.

**Benchmark Definition**

The benchmark measures the performance of two different approaches to concatenate strings:

1. Using the spread operator (`str.concat(...arr);`)
2. Using a `for` loop (`for(let i=0; i<100; i++){\r\n    str.concat(arr[i]);\r\n}`)

**Options Compared**

The benchmark compares the performance of two approaches:

Pros and Cons:

* **Spread Operator (str.concat(...arr));**
	+ Pros:
		- More concise and expressive syntax.
		- Less prone to errors due to its built-in safety features.
	+ Cons:
		- May be slower than the `for` loop approach due to additional overhead for creating an array and iterating over it.
* **For Loop (`for(let i=0; i<100; i++){\r\n    str.concat(arr[i]);\r\n}`)**
	+ Pros:
		- Can be faster due to its direct access to the elements of `arr`.
	+ Cons:
		- More verbose and error-prone syntax.
		- May require more manual memory management.

**Library Used**

There is no specific library mentioned in the provided JSON. The benchmark only uses built-in JavaScript functionality for string concatenation.

**Special JS Features or Syntax**

The benchmark uses the spread operator (`...`) which was introduced in ECMAScript 2015 (ES6). This feature allows for a more concise syntax for spreading elements into an array or other data structure.

**Other Alternatives**

In addition to the two approaches mentioned, there are other ways to concatenate strings in JavaScript:

* Using the `+=` operator: `str += arr[i];`
* Using the `join()` method on an empty string: `str.join(arr)`
* Using a library like Lodash (which provides a `compact` function for concatenating strings)

It's worth noting that the choice of approach depends on the specific use case and personal preference. The spread operator is generally considered more readable and concise, while the `for` loop approach may be faster but requires more manual memory management.

As for the benchmark results, they provide a comparison of the performance of each approach across multiple executions per second. The results can help developers understand which approach to use in different situations, depending on their priorities (readability vs. speed).

Related benchmarks:

String Concatenation with a predefined String Array set (version: 0)

Comparing performance of: concat (w/ spread operator) vs concat using for loop

Created: 3 years ago by: Guest

Jump to the latest result

concat (w/ spread operator)

concat using for loop

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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