Benchmark: Fastest way to do string includes string

Script Preparation code:

window.myString = 'a looooooong string who knows how Long'
window.regexpI = new RegExp('long', 'i');
window.regexp = new RegExp('long');

Tests:

.indexOf
myString.toLocaleLowerCase().indexOf('long') !== -1
includes
myString.toLocaleLowerCase().includes('long')
regex case sensi
myString.toLocaleLowerCase().match(regexp)
regex case insensi
myString.match(regexpI)

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
.indexOf
includes
regex case sensi
regex case insensi

Fastest: N/A

Slowest: N/A

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

LLMs can make mistakes. Check important info.

Let's dive into the world of JavaScript microbenchmarks.

**Benchmark Definition**

The benchmark measures the fastest way to perform string includes (e.g., `includes()`, `indexOf()`). The script preparation code sets up two variables: `myString` and two regular expressions, `regexpI` and `regexp`. The HTML preparation code is empty.

**Options Compared**

Three options are compared:

1. `.includes()`: This method returns a boolean value indicating whether the string contains the specified value.
2. `.indexOf()`: This method returns the index of the first occurrence of the specified value in the string, or -1 if not found.
3. Using regular expressions with `match()` (with and without case sensitivity).

**Pros and Cons**

Here's a brief summary of each option:

* `.includes()`:
	+ Pros: Simple, easy to read, and well-documented.
	+ Cons: May be slower than other methods due to the overhead of creating a boolean value.
* `.indexOf()`: 
	+ Pros: Returns an index, which can be useful for finding the position of a substring in a string. However, it's not always necessary.
	+ Cons: May return -1 if the substring is not found, which could lead to unexpected behavior.
* Regular expressions with `match()`:
	+ Pros: Can match complex patterns and has built-in support for case insensitivity (`i` flag).
	+ Cons: Can be slower than other methods due to the overhead of regular expression compilation.

**Special JS Features**

The test uses a special JavaScript feature called "regex case sensitivity" (denoted by the `i` flag in the `RegExp` constructor). The `i` flag makes the regular expression engine perform a case-insensitive match. There is no other special JavaScript feature mentioned in this benchmark.

**Library Usage**

There are no libraries used in this benchmark.

**Other Considerations**

When choosing between these methods, consider the following:

* If you need to check if a string contains a substring, `.includes()` might be the simplest and most efficient choice.
* If you need to find the position of a substring in a string, `.indexOf()` might be a better option.
* If you need to match complex patterns or work with case-insensitive matches, regular expressions with `match()` might be the way to go.

**Alternatives**

Other alternatives for this benchmark could include:

* Using the `String.prototype.includes()` method (available in modern browsers) instead of `.includes()`
* Using the `String.prototype.indexOf()` method (available in modern browsers) instead of `.indexOf()`
* Adding more complex regular expressions or using other string manipulation methods like `replace()` or `split()`

Keep in mind that the best approach will depend on the specific requirements and constraints of your use case.

Latest run results:

Run details: (Test run date: 9 months ago)

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/121.0.0.0 Safari/537.36

Browser/OS: Chrome 121 on Mac OS X 10.15.7

View result in a separate tab

Test name	Executions per second
.indexOf	12517119.0 Ops/sec
includes	12475868.0 Ops/sec
regex case sensi	5527187.0 Ops/sec
regex case insensi	6327572.5 Ops/sec

Related benchmarks:

Fastest way to do string includes string (version: 0)

Comparing performance of: .indexOf vs includes vs regex case sensi vs regex case insensi

Created: 9 months ago by: Registered User

Jump to the latest result

.indexOf

includes

regex case sensi

regex case insensi

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):