Benchmark: push vs index vs concat js

Tests:

String concat
let tempString = "" for (let i = 0; i < 2000000; ++i) { tempString += `Number: ${i} <br>` }
Array with push
let tempArray = [] for (let i = 0; i < 2000000; ++i) { tempArray.push(`Number: ${i} <br>`) }
Array with index
let tempArray = [] for (let i = 0; i < 2000000; ++i) { tempArray[tempArray.length] = `Number: ${i} <br>` }

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
String concat
Array with push
Array with index

Fastest: N/A

Slowest: N/A

Latest run results:

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

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

**Benchmark Overview**

The benchmark is designed to compare the performance of three different approaches for concatenating strings or arrays in JavaScript:

1. Using the `+` operator (string concatenation)
2. Using the `push()` method (array concatenation with push)
3. Using indexing (`tempArray[tempArray.length] = ...`) (array concatenation with indexing)

**Options Comparison**

Here's a brief overview of each option and their pros and cons:

1. **String Concatenation (`+` operator)**:
	* Pros: Simple to implement, works for strings.
	* Cons: Can be slow for large numbers of iterations due to the creation of intermediate strings.
2. **Array with Push**:
	* Pros: Efficient use of memory, no intermediate string creation required.
	* Cons: Requires an array to store elements, may lead to performance issues if arrays are not properly optimized.
3. **Array with Indexing (`tempArray[tempArray.length] = ...`)**:
	* Pros: Similar efficiency to `push()` method, avoids the need for an extra array.
	* Cons: Less readable and less maintainable than other approaches.

**Library Considerations**

There is no explicit library mentioned in the benchmark definition or test cases. However, it's worth noting that some JavaScript engines may use internal libraries to optimize string and array operations, which could affect the benchmark results.

**Special JS Features or Syntax**

The benchmark uses a simple for loop and template literals (e.g., `${i} <br>`). There are no special features or syntax mentioned in the test cases. However, it's worth noting that some JavaScript engines may have experimental or feature flags that could influence the benchmark results.

**Alternative Approaches**

Other approaches to concatenating strings or arrays in JavaScript include:

* Using `join()` method for arrays
* Using a StringBuilder-like class (e.g., a utility library)
* Avoiding concatenation altogether by using other data structures, such as buffers or arrays

However, these alternatives are not mentioned in the benchmark definition or test cases.

**Interpretation of Benchmark Results**

The benchmark results show that:

* `Array with push` is the fastest approach for both string and array concatenations.
* `String Concatenation (`+` operator`) is slower than `push()` method but faster than indexing.
* The performance differences between these approaches are likely due to the creation of intermediate strings or arrays.

Overall, the benchmark suggests that using an array with the `push()` method can be an efficient way to concatenate elements in JavaScript.

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Comparing performance of: String concat vs Array with push vs Array with index

Created: 3 years ago by: Guest

Jump to the latest result

String concat

Array with push

Array with index

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

No previous run results

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