Benchmark: string concat big string

Script Preparation code:

function generateRandomString(length) {
    var result           = '';
    var characters       = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789';
    var charactersLength = characters.length;
    for ( var i = 0; i < length; i++ ) {
       result += characters.charAt(Math.floor(Math.random() * charactersLength));
    }
    return result;
}


var arr = " ".repeat(100).split(" ").map(x => generateRandomString(3000));

Tests:

Join
arr.join(", ");
Array reduce (how is this so fast?)
arr.reduce( (s, el) => s+el )
Template literals
`${[...arr]}`

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Join
Array reduce (how is this so fast?)
Template literals

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 9 months ago)

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/122.0.0.0 Safari/537.36

Browser/OS: Chrome 122 on Windows

View result in a separate tab

Test name	Executions per second
Join	620.5 Ops/sec
Array reduce (how is this so fast?)	2046133.6 Ops/sec
Template literals	608.9 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 benchmark and explain what's being tested.

**Benchmark Definition JSON**

The provided JSON represents a JavaScript microbenchmarking test case. The main part of this object contains the script preparation code, which generates an array `arr` with 100 random strings of varying lengths (each string is a concatenation of a space character followed by a random alphanumeric string). This creates a large dataset for benchmarking.

**Options being compared**

The benchmark compares three different approaches:

1. **Join**: The `join()` method, which concatenates all elements in the array into a single string using a specified separator.
2. **Array reduce**: The `reduce()` method, which applies a function to each element of the array and reduces it to a single value (in this case, the concatenated string).
3. **Template literals**: A feature introduced in ECMAScript 2015, which allows creating strings with embedded expressions using backticks (`).

**Pros and Cons**

Here's a brief overview of each approach:

1. **Join**:
	* Pros: Simple and straightforward, easy to implement.
	* Cons: Can be slower than other approaches for large datasets due to the overhead of string concatenation.
2. **Array reduce**:
	* Pros: More efficient than `join()` as it avoids creating intermediate strings. It's also a more functional programming style approach.
	* Cons: May have higher memory usage due to the accumulator and can be slower for very large datasets.
3. **Template literals**:
	* Pros: Fast and efficient, especially for smaller datasets. It's also a modern JavaScript feature that provides a concise way of creating strings with embedded expressions.
	* Cons: Limited support in older browsers and may not be as straightforward to implement.

**Library usage**

None of the test cases use any external libraries.

**Special JS features or syntax**

The benchmark uses template literals (`${...}`) for the third test case. Template literals are a feature introduced in ECMAScript 2015, which allows creating strings with embedded expressions using backticks (`). This feature is widely supported by modern browsers and is considered fast and efficient.

**Other alternatives**

If you were to modify this benchmark to include other approaches, here are some options:

1. **Using `concat()`**: Another way to concatenate array elements would be to use the `concat()` method.
2. **Using a `for` loop**: Instead of using `reduce()`, you could use a traditional `for` loop to iterate over the array and build the concatenated string.
3. **Using a library like Lodash**: If you wanted to explore a more functional programming style approach, you could consider using a library like Lodash, which provides a `join()` function.

Keep in mind that modifying this benchmark would require significant changes to the script preparation code and test cases.

Related benchmarks:

string concat big string (version: 0)

Comparing performance of: Join vs Array reduce (how is this so fast?) vs Template literals

Created: 10 months ago by: Guest

Jump to the latest result

Join

Array reduce (how is this so fast?)

Template literals

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):