Benchmark: string += vs array joining vs template strings [v2]

Script Preparation code:

var str, strarr
var chars = 'abcdefghijklmnoprstuwxyz'

Tests:

+=
str = '' while (str.length < 100) str += chars[ Math.floor( Math.random() * chars.length ) ]
array joining
strarr = [] while (strarr.length < 100) strarr.push(chars[ Math.floor( Math.random() * chars.length ) ]) str = strarr.join('')
template strings
str = '' while (str.length < 100) str = `${str}${chars[ Math.floor( Math.random() * chars.length ) ]}`

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
+=
array joining
template strings

Fastest: N/A

Slowest: N/A

Latest run results:

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

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/81.0.4044.142 Safari/537.36

Browser/OS: Chrome 81 on Windows

View result in a separate tab

Test name	Executions per second
+=	11610.1 Ops/sec
array joining	13603.0 Ops/sec
template strings	11610.1 Ops/sec

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

LLMs can make mistakes. Check important info.

Let's break down the provided benchmark and its test cases.

**Overview**
The benchmark compares three ways to concatenate strings in JavaScript: using the `+=` operator, array joining (`strarr.join('')`), and template strings (`${str}${chars[ Math.floor( Math.random() * chars.length ) ]}`).

**Test Cases**

1. **`+=` Operator**: This test case uses a while loop to continuously append characters from the string `chars` to the variable `str`. The number of iterations is controlled by the length of `str`, which starts at 0 and increments until it reaches 100.
2. **Array Joining**: In this test case, an empty array `strarr` is created and populated with characters from `chars` using the `push()` method. Once `strarr` has 100 elements, it's joined into a single string using the `join()` method, and the result is assigned to the variable `str`.
3. **Template Strings**: This test case uses template literals (introduced in ECMAScript 2015) to concatenate strings. The expression `${str}${chars[ Math.floor( Math.random() * chars.length ) ]}` creates a new string by appending the randomly selected character from `chars` to the existing value of `str`.

**Library and Special Features**

* None of the test cases use any external libraries.
* Template literals are used in the third test case, which is a relatively recent feature introduced in ECMAScript 2015. This means that only browsers supporting ES6 or later syntax will be able to execute this test.

**Options Compared**

The benchmark compares three options:

* `+=` operator
* Array joining using the `push()` and `join()` methods
* Template strings

**Pros and Cons of Each Approach**

1. **`+=` Operator**
	* Pros: Simple, easy to understand, and widely supported.
	* Cons: Can lead to string concatenation issues due to performance and security concerns (e.g., creating a new string object on each iteration).
2. **Array Joining**
	* Pros: More efficient than `+=` for large strings, as it avoids the overhead of creating multiple string objects.
	* Cons: Requires an extra array and method call, which can be overkill for simple concatenation tasks.
3. **Template Strings**
	* Pros: Readable, concise, and modern syntax that encourages better coding practices (e.g., using placeholders instead of concatenating strings directly).
	* Cons: Only supported in modern browsers, which might limit its usefulness for older JavaScript environments.

**Other Alternatives**

For string concatenation tasks, other alternatives include:

* Using the `String.prototype.concat()` method
* Utilizing a library like Lodash (which offers a `concat` function)
* Leveraging a template engine or a templating framework

Keep in mind that these alternatives might have their own set of trade-offs and considerations.

I hope this explanation helps you understand the benchmark and its test cases!

Related benchmarks:

string += vs array joining vs template strings [v2] (version: 0)

Comparing performance of: += vs array joining vs template strings

Created: 4 years ago by: Guest

Jump to the latest result

+=

array joining

template strings

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

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