Benchmark: Joining strings - MeasureThat.net

HTML Preparation code:

<!--your preparation HTML code goes here-->

Script Preparation code:

/*your preparation JavaScript code goes here
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const a = [];
async function globalMeasureThatScriptPrepareFunction() {
    // This function is optional, feel free to remove it.
    // await someThing();
  	for(let i = 0; i < 100000; i++) {
      a.push(Math.floor(Math.random() * 1000));
    }
}

Tests:

join
a.join('');
for loop concatenation
let b = ''; for(let j = 0; j < a.length; j++) { b += a[j]; }

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
join
for loop concatenation

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: one year ago)

User agent: Mozilla/5.0 (X11; Linux x86_64; rv:135.0) Gecko/20100101 Firefox/135.0

Browser/OS: Firefox 135 on Linux

View result in a separate tab

Test name	Executions per second
join	696.3 Ops/sec
for loop concatenation	400.3 Ops/sec

Autogenerated LLM Summary (model gpt-4o-mini, generated one year ago):

LLMs can make mistakes. Check important info.

The benchmark defined in the provided JSON tests the performance of two different string concatenation methods in JavaScript using an array filled with random numbers. Here's an explanation of the two approaches compared and their respective pros and cons, along with relevant considerations.

### Benchmark Overview

#### 1. **`a.join('')` (Join Method)**
   - **Description**: This approach uses the `Array.prototype.join()` method to concatenate all elements of the array `a` into a single string, with an empty string as the separator.
   - **Test Name**: Join

#### 2. **`for loop concatenation`**
   - **Description**: This method concatenates strings by iterating through each element of the array `a` using a traditional `for` loop and appending each element to an empty string `b`.
   - **Test Name**: For Loop Concatenation

### Performance Results

In the benchmark results:
- The **join method** achieved approximately **696.28 executions per second**.
- The **for loop concatenation** method achieved approximately **400.34 executions per second**.

### Pros and Cons

#### Join Method
- **Pros**:
  - **Performance**: Generally faster for large arrays since it efficiently allocates space for the resulting string in a single pass.
  - **Conciseness**: Easier to implement and read; one line of code achieves the goal.
  
- **Cons**:
  - **Flexibility**: Less control over how elements are concatenated. If different separators are needed, a modification in the `join()` argument will be required.

#### For Loop Concatenation
- **Pros**:
  - **Flexibility**: Full control over the concatenation process; can accommodate complex logic for concatenation (e.g., conditional additions).
  - **Explicitness**: Some may prefer the clarity of a loop for educational purposes or specific scenarios where more complex operations are required.

- **Cons**:
  - **Performance**: Tends to be slower due to the repeated allocation and deallocation of memory for strings during each iteration.
  - **Verbosity**: Requires more lines of code, which may lead to readability issues in larger scripts.

### Considerations
When choosing between these methods for string concatenation, consider the following:
- **Performance needs**: If performance is a critical factor and the arrays are large, prefer using `Array.prototype.join()` for better execution speed.
- **Readability and maintainability**: If your project's coding standard values clarity and simplicity, `join()` is typically more concise and clear.
- **Use case**: If specific concatenation logic is required, a loop may be necessary despite decreased performance.

### Alternatives
Other alternatives for concatenating strings in JavaScript include:
- **String.prototype.concat()**: This method allows concatenating two or more strings but is usually less common due to clarity and performance reasons.
- **Template literals**: With the introduction of ES6, template literals (`\``) can also be utilized for concatenating strings in a more readable fashion, particularly for complex concatenation that includes variables.
- **Array methods (`map`, `reduce`)**: For more complex scenarios where transformation of data is required along with concatenation, these functional programming approaches can be very powerful, although they may introduce overhead.

Overall, for the specific case of concatenating elements of an array into a single string, the benchmark indicates that using `.join('')` is the most efficient method in JavaScript.

Related benchmarks:

Joining strings (version: 1)

Comparing performance of: join vs for loop concatenation

Created: one year ago by: Guest

Jump to the latest result

join

for loop concatenation

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model gpt-4o-mini, generated one year ago):