Benchmark: RegExp vs substring

Script Preparation code:

function getRandomInt(max) {
    return Math.floor(Math.random() * Math.floor(max));
}
var arr = [];
for (i = 0; i < 1000; i++) {
    arr.push("PROPERTY_" + getRandomInt(10000));
    arr.push("RUS_" + getRandomInt(10000));
}
var success = 0;

Tests:

RegExp
for(const value of arr) { if(/^PROPERTY_/.test(value)) success++; }
substring
for(const value of arr) { if(value.substring(0, 9) === "PROPERTY_") success++; }

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
RegExp
substring

Fastest: N/A

Slowest: N/A

Latest run results:

No previous run results

This benchmark does not have any results yet. Be the first one to run it!

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 and its options.

**Benchmark Overview**

The benchmark compares two approaches to test strings for a specific property: using `RegExp` or `substring`.

**Options Compared**

There are two test cases:

1. **RegExp**: This approach uses a regular expression (`/^PROPERTY_/`) to check if the string starts with "PROPERTY_".
2. **substring**: This approach uses the `substring` method to extract the first 9 characters of the string and checks if it matches "PROPERTY_".

**Pros and Cons**

**RegExp**

Pros:

* More flexible and powerful for complex pattern matching
* Can be used to perform more advanced operations, such as matching multiple patterns or performing case-insensitive matching

Cons:

* May be slower due to the overhead of compiling a regular expression
* Can be affected by optimizations, which may not always favor performance

**substring**

Pros:

* Typically faster and more optimized than RegExp for simple string manipulation
* Does not require compilation or parsing like RegExp does

Cons:

* Less flexible and powerful compared to RegExp
* May not perform well for complex pattern matching or larger strings

**Other Considerations**

* Both approaches have their strengths and weaknesses, making the choice between them often a trade-off between performance, flexibility, and code simplicity.
* In general, if you need to perform simple string testing with specific patterns, `substring` might be a better choice. However, for more complex pattern matching or advanced operations, `RegExp` is usually the better option.

**Library Usage**

Neither of the approaches uses any external libraries. They are built-in JavaScript methods and functions that can be used directly in most JavaScript applications.

**Special JS Features/Syntax**

The benchmark does not use any special JavaScript features or syntax beyond what's standard for modern JavaScript. However, if you're interested in exploring more advanced options, some popular alternatives to `RegExp` include:

* `String.prototype.match()`: This method returns an array of matches if the string passes a pattern test, allowing for more flexibility than `RegExp`.
* `String.prototype.indexOf()`: This method returns the index of the first occurrence of a specified value, which can be used in combination with other methods to achieve similar results to `RegExp`.

**Other Alternatives**

For comparing different JavaScript implementations or optimizing specific parts of your codebase, you might want to explore:

* WebAssembly (WASM): A binary format that allows for compiled languages like C and C++ to run in web browsers, potentially improving performance.
* V8 Inspector: A tool provided by the Chrome team to inspect and debug V8's JavaScript engine, offering insights into its inner workings and potential optimization paths.
* jsperf: An online benchmarking platform for testing JavaScript code, allowing you to compare different implementations and identify performance bottlenecks.

Related benchmarks:

RegExp vs substring (version: 1)

Comparing performance of: RegExp vs substring

Created: 5 years ago by: Registered User

Jump to the latest result

RegExp

substring

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

No previous run results

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