Benchmark: strig concatenation vs array acc

Tests:

string concatenation
let str = ''; for (let i; i < 10_000; i++) { str += i; }
array accumulator
const acc = []; for (let i; i < 10_000; i++) { acc.push(i); } acc.join('');
array accumulator without glue
const acc = []; for (let i; i < 10_000; i++) { acc.push(i); } acc.join();

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
string concatenation
array accumulator
array accumulator without glue

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: one year ago)

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/125.0.0.0 Safari/537.36

Browser/OS: Chrome 125 on Mac OS X 10.15.7

View result in a separate tab

Test name	Executions per second
string concatenation	179095344.0 Ops/sec
array accumulator	100222712.0 Ops/sec
array accumulator without glue	105550808.0 Ops/sec

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

LLMs can make mistakes. Check important info.

I'll break down the provided benchmark and explain what's being tested, compared, and their pros/cons.

**Benchmark Overview**

The test measures the performance of string concatenation versus two approaches for array accumulation: with glue (`acc.join('')`) and without glue (`acc.push(i)` followed by `acc.join('')`).

**Test Cases**

1. **String Concatenation**
	* Benchmark Definition:
```javascript
let str = '';
for (let i; i < 10_000; i++) {
    str += i;
}
```
This test case concatenates numbers from 0 to 9,999 using the `+` operator.
2. **Array Accumulator with Glue**
	* Benchmark Definition:
```javascript
const acc = [];
for (let i; i < 10_000; i++) {
    acc.push(i);
}
acc.join('');
```
This test case accumulates numbers from 0 to 9,999 in an array (`acc`) and then joins the elements using the `join()` method with an empty string as glue.
3. **Array Accumulator without Glue**
	* Benchmark Definition:
```javascript
const acc = [];
for (let i; i < 10_000; i++) {
    acc.push(i);
}
acc.join('');
```
This test case is similar to the previous one, but it does not use glue (`join('')`) when joining the array elements.

**Performance Comparison**

The test measures the execution speed of each approach. The performance results are presented in the benchmark output as `ExecutionsPerSecond` values for each browser and device platform.

**Pros and Cons of Each Approach:**

1. **String Concatenation**
	* Pros:
		+ Simple and easy to understand.
	* Cons:
		+ Performance is poor due to the creation of a new string object on each iteration.
2. **Array Accumulator with Glue**
	* Pros:
		+ More efficient than concatenating strings, as it avoids creating intermediate objects.
	* Cons:
		+ Requires an additional join operation at the end, which can introduce overhead.
3. **Array Accumulator without Glue**
	* Pros:
		+ Similar to the previous approach, but with no additional glue overhead.
	* Cons:
		+ Still requires joining the array elements, which may incur some overhead.

**Library and Special JS Features**

In this benchmark, the `join()` method is used in two test cases. The `join()` method is a built-in JavaScript method that concatenates an array of values into a single string, using a specified separator (in this case, an empty string).

No special JavaScript features or syntax are used beyond what's required for these basic operations.

**Alternatives**

If you're looking to optimize string concatenation, consider the following alternatives:

1. **Use `Array.prototype.join()`**: This approach is more efficient than concatenating strings using the `+` operator.
2. **Use a template engine**: Template engines like Handlebars or Mustache can handle string interpolation and concatenation more efficiently than JavaScript's built-in methods.
3. **Preallocate memory**: For large datasets, preallocating memory for the result can improve performance by reducing the overhead of creating intermediate objects.

Keep in mind that these alternatives may introduce additional dependencies or complexity, so choose them carefully depending on your specific use case and requirements.

Related benchmarks:

strig concatenation vs array acc (version: 0)

Comparing performance of: string concatenation vs array accumulator vs array accumulator without glue

Created: one year ago by: Guest

Jump to the latest result

string concatenation

array accumulator

array accumulator without glue

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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