Benchmark: Benchmark .replace() VS edit index in place + .join() at the end

Script Preparation code:

var testString = 'aa bb cc dd ee ff gg hh ii jj kk ll mm nn oo pp qq rr ss tt uu vv ww xx yy zz';
var testArray = testString.split(" ");

function replaceInString() {
  testString.replace(/aa/, "11");
  testString.replace(/bb/, "22");
  testString.replace(/mm/, "33");
  testString.replace(/nn/, "44");
  testString.replace(/yy/, "55");
  testString.replace(/zz/, "66");
}

function updateInArrayAndJoin() {
  testArray[0] = "11";
  testArray[1] = "22";
  testArray[12] = "33";
  testArray[13] = "44";
  testArray[24] = "55";
  testArray[25] = "66";
  testArray.join(" ")
}

Tests:

replaceInString
replaceInString()
updateInArrayAndJoin
updateInArrayAndJoin()

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
replaceInString
updateInArrayAndJoin

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 27 days ago):

LLMs can make mistakes. Check important info.

**Overview of the Benchmark**

MeasureThat.net is a website that allows users to create and run JavaScript microbenchmarks. The provided JSON represents a benchmark with two test cases: `replaceInString()` and `updateInArrayAndJoin()`. The goal of this benchmark is to compare the performance of two approaches for updating a string and an array in place.

**Test Case 1: `replaceInString()`**

This test case uses the `.replace()` method to update the characters in the `testString` variable. The method is called multiple times with different regular expressions, replacing specific substrings with new values.

**Pros of using `.replace()`**

* Easy to implement and understand
* Fast and efficient for small-scale updates

**Cons of using `.replace()`**

* Can be slower than other methods for large-scale updates due to the overhead of creating a new string and updating the original
* May not be suitable for cases where the replacement is complex or involves multiple operations

**Test Case 2: `updateInArrayAndJoin()`**

This test case updates an array in place by assigning new values to specific elements. The updated array is then joined into a string using the `.join()` method.

**Pros of using `updateInArrayAndJoin()`**

* Can be faster than `.replace()` for large-scale updates, as it avoids creating a new string
* Suitable for cases where the update involves multiple operations or complex logic

**Cons of using `updateInArrayAndJoin()`**

* Requires manual indexing and assignment to update individual elements in the array
* May not be suitable for cases where the update is complex or involves multiple operations

**Library Used: `join()` method**

The `.join()` method is a built-in JavaScript method that concatenates an array of values into a single string, separated by a specified separator. In this benchmark, it is used to join the updated array back into a string.

**Special JS Feature/Syntax: None mentioned in the provided code snippet**

However, it's worth noting that some browsers may optimize certain methods or syntax, such as `for...of` loops or `let`/`const` declarations, which can affect benchmark results.

**Alternatives to these approaches**

Other methods for updating strings and arrays include:

* Using a library like Lodash or Underscore.js, which provide optimized implementations of `.replace()` and array update operations.
* Using a custom implementation with native WebAssembly (WASM) code, which can provide optimal performance for large-scale updates.
* Using a JavaScript interpreter like V8 or SpiderMonkey, which can optimize certain methods and syntax for better performance.

In summary, the benchmark compares two approaches for updating strings and arrays in place: using `.replace()` to update individual characters, and using `updateInArrayAndJoin()` to update multiple elements in an array. The choice of approach depends on the specific use case, performance requirements, and personal preference.

Latest run results:

Run details: (Test run date: 2 years ago)

User agent: Mozilla/5.0 (X11; CrOS x86_64 14909.100.0) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/104.0.0.0 Safari/537.36

Browser/OS: Chrome 104 on Chrome OS 14909.100.0

View result in a separate tab

Test name	Executions per second
replaceInString	313857.4 Ops/sec
updateInArrayAndJoin	303543.3 Ops/sec

Related benchmarks:

Benchmark .replace() VS edit index in place + .join() at the end (version: 0)

Comparing performance of: replaceInString vs updateInArrayAndJoin

Created: 2 years ago by: Guest

Jump to the latest result

replaceInString

updateInArrayAndJoin

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 27 days ago):