Benchmark: String each replace - for vs foreach vs reduce

Script Preparation code:

var arr = Array.from({ length: 20000 });
var str = arr.reduce((acc, v, i) => `${acc}{{${i}}}`, '');

Tests:

for
for (let i = 0; i < arr.length; i += 1) { str = str.replace(`{{${i}}}`, `((${i}))`); }
foreach
arr.forEach((v, i) => { str = str.replace(`{{${i}}}`, `((${i}))`); });
reduce
str = arr.reduce((acc, v, i) => acc.replace(`{{${i}}}`, `((${i}))`), str);

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
for
foreach
reduce

Fastest: N/A

Slowest: N/A

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

LLMs can make mistakes. Check important info.

The provided JSON represents a benchmark test on MeasureThat.net, which compares the performance of three different approaches for replacing a pattern in a string:

1.  For loop: This approach uses a traditional for loop to iterate over an array and replace a specific pattern in a string.

2.  Foreach loop: This approach utilizes the `forEach` method provided by arrays to iterate over each element and perform the replacement.

3.  Reduce function: This approach leverages the `reduce` function, which applies a callback function to each element of an array (from left to right) and reduces it to a single output value.

**Options Compared**

The three approaches are compared in terms of their performance:

*   For loop
*   Foreach loop
*   Reduce function

Each approach has its own strengths and weaknesses, which are discussed below.

**Pros and Cons**

1.  **For Loop:**
    *   Pros:
        *   Easy to understand and implement.
        *   Works well for simple iterations.
    *   Cons:
        *   Can be slower due to the overhead of a loop control block.
        *   Requires manual index management (in this case, `i += 1`).

2.  **Foreach Loop:**
    *   Pros:
        *   More concise and readable than traditional for loops.
        *   Reduces the chance of off-by-one errors when indexing elements.
    *   Cons:
        *   May incur a slight overhead due to method call and iteration.

3.  **Reduce Function:**
    *   Pros:
        *   Highly optimized by V8 (the JavaScript engine used in Chrome).
        *   Can be very efficient for large datasets, especially when compared to other options.
    *   Cons:
        *   May require additional setup or familiarity with the `reduce` function.
        *   Less intuitive than traditional loops.

**Library/Functionality:**

In this benchmark, the `Array.prototype.forEach()` and `Array.prototype.reduce()` methods are utilized. These functions are part of the JavaScript standard library and provide efficient ways to work with arrays in various contexts.

*   **Array.prototype.forEach()**: This method iterates over an array, allowing each element's value (or a block of code) to be executed. It provides more flexibility compared to traditional for loops.
*   **Array.prototype.reduce()**: This method applies a callback function to each element of an array and returns the accumulated result.

**Special JS Features/Syntax:**

This benchmark uses:

1.  **Template literals (`${expression}`)**: These are used to concatenate strings with variable values or expressions, providing a convenient way to build dynamic strings.
2.  **Arrow functions (`(argument) => expression`)**: These are concise ways to define small, single-expression functions.

**Other Alternatives:**

While the three approaches mentioned earlier might be some of the most common methods for string replacements in JavaScript, there are other alternatives:

1.  **Using regular expressions (regex):**
    *   Regex can provide more flexibility and control when dealing with complex patterns.
2.  **Utilizing `String.prototype.replace()` method:**
    *   This is a straightforward way to replace parts of a string.

Note that the choice of approach depends on specific use cases, performance requirements, and personal preference.

Latest run results:

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

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/117.0.0.0 Safari/537.36

Browser/OS: Chrome 117 on Mac OS X 10.15.7

View result in a separate tab

Test name	Executions per second
for	12.0 Ops/sec
foreach	14.8 Ops/sec
reduce	17.7 Ops/sec

Related benchmarks:

String each replace - for vs foreach vs reduce (version: 0)

Comparing performance of: for vs foreach vs reduce

Created: one year ago by: Guest

Jump to the latest result

for

foreach

reduce

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):