Benchmark: Split string vs. regex

Script Preparation code:

var a = 'dynamicProduct:abc';

Tests:

string
console.log(a.split(':'))
regex
console.log(a.split(/:(?![^{]*})/g))

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
string
regex

Fastest: N/A

Slowest: N/A

Latest run results:

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

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/120.0.0.0 Safari/537.36

Browser/OS: Chrome 120 on Mac OS X 10.15.7

View result in a separate tab

Test name	Executions per second
string	337144.2 Ops/sec
regex	339228.3 Ops/sec

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

LLMs can make mistakes. Check important info.

Let's break down what's being tested in the provided benchmark.

**Benchmark Definition**

The benchmark is designed to compare two approaches for splitting a string:

1. `split(':')`
2. `split(/:(?![^{]*})/g)`

**What are we comparing?**

We're comparing the performance of these two approaches:

* **Literal Split**: The first approach uses the literal `:` character as the separator to split the string.
* **Regular Expression (Regex) Split**: The second approach uses a regular expression (`/(:(?![^{]*})/g)/`) that matches the `:` character only if it's not followed by zero or more characters (`[^]*`). This is a negative lookahead assertion.

**Pros and Cons**

### Literal Split

Pros:

* Simple and easy to understand
* Fast, since it doesn't require parsing regular expressions
* Works well for simple string splitting tasks

Cons:

* May not work correctly if the separator character has special meaning in the context (e.g., `:` is used as a delimiter in an array)

### Regex Split

Pros:

* More flexible and powerful than literal split, can handle complex separator logic
* Can be used to extract specific parts of the string based on pattern matching

Cons:

* Slower due to the overhead of parsing regular expressions
* More prone to errors if the regex is not well-defined or edge cases are not handled properly

**Other Considerations**

* The test assumes that the input string `a` contains a `:` character, which may not always be the case. Handling this scenario might require additional logic.
* The `(?![^{]*})` part in the regex ensures that the separator is not followed by any characters (including newline). If this is not the desired behavior, it can be adjusted.

**Library and Special JS Feature**

Neither of the approaches relies on a specific library or special JavaScript feature. However, if you were to modify the test to use more advanced string manipulation methods (e.g., `String.prototype.split()` with options), that would involve additional libraries or features not present in this benchmark.

**Alternatives**

Some alternative approaches for splitting strings include:

* Using an external library like `lodash` which provides a robust and flexible way to split strings
* Using a more modern JavaScript feature like template literals (`${separator}${string}`) to avoid string concatenation altogether
* Implementing a custom string splitting function with iteration or using a data structure like a trie for efficient lookup

These alternatives would require changes to the benchmark setup, but they could provide additional insights into performance and efficiency under different scenarios.

Related benchmarks:

Split string vs. regex (version: 0)

Comparing performance of: string vs regex

Created: 2 years ago by: Guest

Jump to the latest result

string

regex

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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