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

Script Preparation code:

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

Tests:

concat()
var message = string1.concat(string2);
plus_operator
var message = string1 + string2;

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
concat()
plus_operator

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 8 years ago)

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_11_6) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/55.0.2861.0 Safari/537.36

Browser/OS: Chrome 55 on Mac OS X 10.11.6

View result in a separate tab

Test name	Executions per second
concat()	3927271.0 Ops/sec
plus_operator	4031846.5 Ops/sec

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

LLMs can make mistakes. Check important info.

Let's break down the provided benchmark.

**What is being tested?**

The website, MeasureThat.net, is testing the performance difference between two approaches: using the `concat()` method and the `+` operator for concatenating strings in JavaScript.

**Options compared**

Two options are compared:

1. `concat()`: This is a built-in JavaScript method that concatenates two or more strings together.
2. `+` (the addition operator): In JavaScript, when you use the `+` operator with string literals, it concatenates them instead of performing arithmetic addition.

**Pros and Cons**

Here are some pros and cons of each approach:

* `concat()`
	+ Pros:
		- Explicitly intended for string concatenation.
		- May be more readable in code that requires multiple concatenations.
		- Supports multiple arguments, making it flexible for handling longer strings or multiple strings to concatenate.
	+ Cons:
		- Can be slower due to the overhead of calling a method.
* `+`
	+ Pros:
		- Often faster than using the `concat()` method since it's just an operator and doesn't involve a function call.
		- May be more efficient in older JavaScript engines or those with limited caching.
	+ Cons:
		- Less explicit and may lead to unexpected behavior if not used correctly (e.g., concatenating numbers instead of strings).
		- Can make code harder to read, especially for developers unfamiliar with this usage.

**Library**

There is no library explicitly mentioned in the benchmark. However, both `concat()` and the `+` operator are built-in JavaScript methods.

**Special JS feature or syntax**

The test case doesn't use any special JavaScript features or syntax other than string concatenation. It's a straightforward comparison of two common ways to concatenate strings.

**Other alternatives**

If you wanted to explore alternative approaches, here are some options:

* Using the `StringBuilder` class from the TypeScript compiler (not supported in all browsers): This can be faster for large strings.
* Using an array and joining it with `join()`: This approach avoids creating intermediate results and may be more efficient.

Here's a basic example of how you could rewrite the test case using these alternatives:
```javascript
// StringBuilder example
var sb = new StringBuilder();
sb.append(string1).append(string2);
var message = sb.toString();

// Array and join() example
var arr = [string1, string2];
var message = arr.join('');
```
Keep in mind that these alternatives may have different performance characteristics and might not be supported by all browsers or JavaScript engines.

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

Created: 8 years ago by: Guest

Jump to the latest result

concat()

plus_operator

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

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