Benchmark: replaceAll vs replace with /g

Tests:

replace regex
"this is it".replace(/ /g, "+");
replace All
"this is it".replaceAll(" ", "+");

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
replace regex
replace All

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; rv:141.0) Gecko/20100101 Firefox/141.0

Browser/OS: Firefox 141 on Windows

View result in a separate tab

Test name	Executions per second
replace regex	13125861.0 Ops/sec
replace All	27444916.0 Ops/sec

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

LLMs can make mistakes. Check important info.

Let's break down the provided benchmark JSON and explain what's being tested, along with the pros and cons of each approach.

**What is being tested?**

The benchmark compares two different methods for replacing whitespace characters in a string:

1. `replace()`: This method uses a regular expression to replace all occurrences of a specified value (in this case, whitespace characters) with another specified value.
2. `replaceAll()`: This method uses a non-regex-based replacement mechanism that replaces all occurrences of a specified value with another specified value.

**Options compared**

The benchmark compares the performance of these two methods in the following scenarios:

* Replacing whitespace characters (`"   "`)

The pros and cons of each approach are as follows:

**replace()**

Pros:

* More flexible, allowing for more complex replacements using regular expressions
* Can be used with various types of whitespace characters (e.g., tabs, line breaks)
* Often considered a safer choice, as it allows for more precise control over the replacement process

Cons:

* May have slower performance due to the overhead of compiling and executing regular expressions
* Can be more difficult to debug and understand, especially for non-regex experts

**replaceAll()**

Pros:

* Typically faster than `replace()`, as it avoids the overhead of compiling and executing regular expressions
* Often preferred in certain situations (e.g., when working with legacy code or optimizing performance-critical sections)

Cons:

* Less flexible, requiring a fixed set of whitespace characters to replace
* May not be suitable for more complex replacement scenarios

**Other considerations**

The benchmark uses a simple string literal (`"this is it"` ) as the test subject. This choice simplifies the comparison but might not reflect real-world usage, where strings may contain various types of data.

If you were to expand this benchmark, you could consider using more realistic test subjects (e.g., strings with Unicode characters) and adding additional scenarios to account for different edge cases.

**Library/Feature: Regular Expressions**

The `replace()` method uses regular expressions to perform the replacement. In JavaScript, regular expressions are a powerful feature that allows for pattern matching, validation, and text manipulation. They are widely used in many programming contexts, including web development, data processing, and security-related tasks.

**Special JS feature/syntax: None mentioned**

There is no mention of any special JavaScript features or syntax being used beyond the `replace()` and `replaceAll()` methods.

Related benchmarks:

replaceAll vs replace with /g (version: 0)

Comparing performance of: replace regex vs replace All

Created: 3 years ago by: Guest

Jump to the latest result

replace regex

replace All

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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