Benchmark: string concatenation vs array acc

Tests:

concatenation
let str = ''; for (let i = 0; i < 10_000; i++) { str += i; }
arr acc
const acc = []; for (let i = 0; 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
concatenation
arr acc

Fastest: N/A

Slowest: N/A

Latest run results:

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

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/125.0.0.0 Safari/537.36 Edg/125.0.0.0

Browser/OS: Chrome 125 on Windows

View result in a separate tab

Test name	Executions per second
concatenation	22094.4 Ops/sec
arr acc	5325.7 Ops/sec

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

LLMs can make mistakes. Check important info.

I'd be happy to help explain the benchmark and its options.

**Benchmark Overview**

The provided JSON represents a JavaScript microbenchmark on MeasureThat.net, which compares two approaches for string concatenation: using the `+` operator (`string concatenation`) versus using the Array `push()` method followed by `join()` (`array acc`). The goal is to determine which approach is faster and more efficient.

**Options Compared**

There are two main options being compared:

1. **String Concatenation**: Using the `+` operator to concatenate strings, e.g., `str += i;`.
2. **Array Accumulation with Join**: Using the Array `push()` method to accumulate elements and then joining them using the `join()` method, e.g., `acc.push(i) && acc.join();`.

**Pros and Cons of Each Approach**

**String Concatenation**

Pros:

* Easy to understand and implement
* Works well for small strings

Cons:

* Creates a new string object in each iteration, leading to slow performance due to the overhead of creating a new string object and copying the contents.
* Not suitable for large strings or frequent concatenations.

**Array Accumulation with Join**

Pros:

* More efficient than string concatenation, as it avoids creating new string objects.
* Suitable for large strings or frequent concatenations.

Cons:

* Requires using an Array to accumulate elements, which can be slower due to the overhead of Array operations.
* May require additional processing to convert individual elements to a format that can be joined (e.g., converting integers to strings).

**Library and Special JS Features**

There is no explicit library mentioned in the benchmark definition or test cases. However, the use of `const` and `let` keywords suggests that this benchmark targets modern JavaScript environments.

No special JavaScript features are explicitly used in these test cases.

**Benchmark Preparation Code**

The preparation code for each test case is null, which means that the benchmarking framework will automatically generate a basic script to execute the specified benchmarks.

**Other Alternatives**

For string concatenation:

* Using a `StringBuilder` class (not natively supported in JavaScript) or a library like `lodash.string` can provide more efficient concatenation.
* Utilizing a `StringBuffer` class (e.g., from the `buffer` module in Node.js) can offer better performance.

For array accumulation with join:

* Using an existing array data structure, such as `Array.prototype.concat()` or `Array.prototype.push()`, can be faster than using `push()` followed by `join()`.
* Leveraging libraries like `lodash.array` or `underscore.collection` for optimized array manipulation and joining.

Keep in mind that the performance difference between these alternatives may vary depending on the specific use case, JavaScript environment, and other factors.

Related benchmarks:

string concatenation vs array acc (version: 0)

Comparing performance of: concatenation vs arr acc

Created: one year ago by: Guest

Jump to the latest result

concatenation

arr acc

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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