Benchmark: startswith vs includes (leading part of string)

Tests:

includes
const str = "https://firebase.com/this/is/a/long/thing" str.includes("https://firebase")
startsWith
const str = "https://firebase.com/this/is/a/long/thing" str.startsWith("https://firebase")

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
includes
startsWith

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: one year ago)

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/110.0.0.0 Safari/537.36 Edg/110.0.1587.41

Browser/OS: Chrome 110 on Mac OS X 10.15.7

View result in a separate tab

Test name	Executions per second
includes	1025938176.0 Ops/sec
startsWith	26575202.0 Ops/sec

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

LLMs can make mistakes. Check important info.

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

**Benchmark Definition**

The benchmark is defined by a JSON object that contains information about the test case, including:

* `Name`: A unique name for the benchmark.
* `Description`: An optional description of the benchmark.
* `Script Preparation Code` and `Html Preparation Code`: These fields are empty in this case, which means no custom setup code is required.

**Individual Test Cases**

There are two test cases:

1. `includes`
	* Benchmark Definition: Tests whether the string "https://firebase.com/this/is/a/long/thing" includes a leading substring of the same string.
	* Script Preparation Code and Html Preparation Code are empty, as no custom setup is required for this test.
2. `startsWith`
	* Benchmark Definition: Tests whether the string "https://firebase.com/this/is/a/long/thing" starts with a specific leading substring.

**Comparison**

The two tests compare the performance of the `includes` method versus the `startsWith` method in JavaScript. Both methods are used to search for a pattern within a string, but they differ in their approach:

* `includes` performs a substring search, which involves iterating over the entire string and checking if the specified substring is present.
* `startsWith` performs an initial character comparison, which quickly discards most of the string as not matching.

**Pros and Cons**

Here are some pros and cons of each approach:

* `includes`:
	+ Pros: Can be faster for longer strings or when searching for a specific substring.
	+ Cons: May have higher overhead due to unnecessary iterations.
* `startsWith`:
	+ Pros: Faster and more efficient for initial character comparisons, as it quickly discards most of the string.
	+ Cons: May be slower if the search involves an empty string or a leading whitespace character.

**Library Usage**

There is no library explicitly mentioned in the benchmark definition. However, some JavaScript implementations might use internal libraries or optimized functions that can affect performance.

**Special JS Feature/Syntax**

There are two special features used in this benchmark:

1. `\r\n`: This is a newline escape sequence, often used to represent a line break in a string.
2. `const` and `let`/`var` declarations: These are modern JavaScript syntax features that declare variables without reassigning them.

**Other Alternatives**

If you're looking for alternative methods or optimizations for substring searches, consider the following:

1. RegEx (Regular Expressions): A powerful pattern-matching language that can be used to search for patterns within strings.
2. `String.prototype.indexOf()` and `String.prototype.lastIndexOf()`: These methods provide more control over the search process but may offer better performance for specific use cases.

In this benchmark, using `includes` versus `startsWith` is a reasonable approach, as it highlights the differences in their implementation and the potential impact on performance.

Related benchmarks:

startswith vs includes (leading part of string) (version: 0)

Comparing performance of: includes vs startsWith

Created: one year ago by: Guest

Jump to the latest result

includes

startsWith

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

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