Benchmark: Javascript 'concat()' vs '+' for strings

Script Preparation code:

var string1 = "Hello ";
var string2 = " world!";

Tests:

concat()
for(i = 0; i < 1000; i++) { var message = string1.concat(string2); }
plus_operator
for(i = 0; i < 1000; i++) { var message = string1 + string2; }
plus_eq_operator
for(i = 0; i < 1000; i++) { string1 += string2; }

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
concat()
plus_operator
plus_eq_operator

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 26 days ago):

LLMs can make mistakes. Check important info.

Let's break down the provided JSON and explain what is tested, compared, and some considerations.

**Benchmark Definition**

The benchmark tests the performance difference between three approaches for concatenating strings in JavaScript:

1. `concat()`
2. The `+` operator (also known as string interpolation)
3. The `+=` assignment operator

These approaches are used to concatenate two string literals: `"Hello "` and `" world!"`.

**Options Compared**

The benchmark compares the performance of these three approaches on a large number of executions:

* `concat()`: A method call that concatenates two strings.
* `+` operator: String interpolation, where the `+` symbol is used to concatenate strings.
* `+=` assignment operator: String augmentation, where the `+=` symbol is used to concatenate strings.

**Pros and Cons**

Here's a brief summary of the pros and cons of each approach:

1. **concat()**:
	* Pros: Explicit method call, easy to read, and maintainable code.
	* Cons: May incur a function call overhead due to the `concat()` method invocation.
2. **+` operator`**:
	* Pros: Fast and efficient, as it uses a native string operation.
	* Cons: Less readable than explicit methods or assignment operators, and may be less intuitive for developers unfamiliar with this syntax.
3. **+=` assignment operator`**:
	* Pros: Fast and efficient, as it uses a native string operation.
	* Cons: May lead to unexpected behavior if not used carefully (e.g., modifying the original string).

**Library Used**

The benchmark doesn't explicitly use any libraries. However, it relies on JavaScript's built-in functionality for concatenating strings.

**Special JS Feature or Syntax**

There is no specific special feature or syntax mentioned in the benchmark definition. The focus is solely on comparing different approaches for string concatenation.

**Other Considerations**

When testing performance-critical code, consider the following:

* Use representative input data: Ensure that the test cases cover a range of scenarios to provide accurate results.
* Optimize for common use cases: If possible, focus on optimizing the most frequently used cases.
* Avoid introducing unnecessary overhead: Minimize any additional complexity or computations beyond what's necessary for the benchmark.

**Alternatives**

If you're looking for alternative approaches to test, consider:

* Using a different programming language (e.g., C++, Java) for concatenation operations.
* Testing the performance of other string manipulation methods, such as using regular expressions or array concatenation.
* Evaluating the impact of caching or memoization on string concatenation performance.

Keep in mind that this benchmark focuses specifically on JavaScript and string concatenation. If you're looking for broader insights into performance optimization, consider more general-purpose benchmarks or testing frameworks.

Latest run results:

Run details: (Test run date: 4 years ago)

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_6) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/84.0.4147.135 Safari/537.36

Browser/OS: Chrome 84 on Mac OS X 10.15.6

View result in a separate tab

Test name	Executions per second
concat()	7898.5 Ops/sec
plus_operator	7727.5 Ops/sec
plus_eq_operator	3007.9 Ops/sec

Related benchmarks:

Javascript 'concat()' vs '+' for strings (version: 0)

Testing the performance difference between concat() and the + operator for strings in javascript

Comparing performance of: concat() vs plus_operator vs plus_eq_operator

Created: 8 years ago by: Guest

Jump to the latest result

concat()

plus_operator

plus_eq_operator

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 26 days ago):