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; }

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:

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

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Let's dive into the explanation of the provided benchmark.

**What is being tested?**

The test measures the performance difference between using the `concat()` method and the `+` operator for concatenating strings in JavaScript.

In other words, it's testing which approach is faster when you need to join two strings together. This is a common scenario in many JavaScript applications, especially when dealing with strings that contain dynamic data or require multiple concatenations.

**Options compared:**

Two options are being tested:

1. `concat()`: A built-in method for concatenating strings.
2. The `+` operator (also known as the "string concatenation" operator): A shorthand way to concatenate strings using the `+` symbol.

**Pros and Cons of each approach:**

* **concat():**
	+ Pros:
		- Can be used with other methods, such as `split()` or `join()`, which can be useful in certain contexts.
		- Does not perform a temporary string creation, reducing memory allocation and garbage collection overhead.
	+ Cons:
		- Can be slower than the `+` operator due to method call overhead.
* **+ operator:**
	+ Pros:
		- Generally faster than `concat()` since it avoids the method call overhead.
		- Can be more readable when working with simple concatenations, as it's a single operation instead of a method call.
	+ Cons:
		- Does create a temporary string, which can lead to increased memory allocation and garbage collection overhead for large strings.

**Library usage:**

There is no explicit library usage mentioned in the benchmark definition. However, since both `concat()` and the `+` operator rely on JavaScript's built-in string handling mechanisms, they are not specific to any particular library.

**Special JS feature/syntax:**

This benchmark does not use any special JavaScript features or syntax beyond standard language features. It only tests the performance difference between two common concatenation methods.

**Other alternatives:**

While `concat()` and the `+` operator are the most common approaches, there are other ways to concatenate strings in JavaScript:

* **template literals**: Introduced in ECMAScript 2015 (ES6), template literals provide a more readable way to concatenate strings with placeholders for variables.
	+ Example: `const message = `${string1} ${string2}`;`
* **Array.join()**: Can be used to concatenate an array of strings into a single string.
	+ Example: `const message = Array.prototype.join.call([string1, string2], '')`

Keep in mind that template literals and `Array.join()` are generally more expressive and flexible than using the `+` operator or `concat()` for simple concatenations. However, they may incur additional overhead due to parsing and creation of intermediate objects.

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: 9 years ago by: Guest

Jump to the latest result

concat()

plus_operator

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):