Benchmark: startswith vs includes (exact 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:

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

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Let's dive into the details of the MeasureThat.net benchmark.

**What is being tested?**

The benchmark measures the performance difference between two string manipulation methods: `includes` and `startsWith`. Specifically, it tests how fast these methods can check if a given string starts with or includes another specific substring (`"https://firebase/"`).

**Options compared**

There are two options being compared:

1. **String.prototype.includes()**: This method checks if the string contains the specified value anywhere in its sequence.
2. **String.prototype.startsWith()**: This method checks if the string starts with the specified value.

**Pros and Cons of each approach:**

1. **String.prototype.includes()**
	* Pros:
		+ More flexible, as it can check for any substring within the string, not just a prefix.
		+ Can be more efficient in some cases, as it only needs to scan the string until it finds the first match.
	* Cons:
		+ Typically slower than `startsWith` because of the scanning process.
2. **String.prototype.startsWith()**
	* Pros:
		+ Faster, especially for short strings or prefixes that appear early on in the original string.
		+ Can be more efficient when working with long strings, as it only needs to check the initial characters.
	* Cons:
		+ Less flexible than `includes`, as it only checks for a specific prefix.

**Other considerations:**

1. **Regular expressions**: Some browsers and engines use regular expressions under the hood for both `includes` and `startsWith`. This can affect performance, as regex processing can be more computationally intensive.
2. **Optimizations**: Modern JavaScript engines often have optimizations in place to improve performance for common string operations like these.

**Special JS feature:**

There is no special JavaScript feature or syntax being used here; the focus is on a fundamental operation that's widely applicable.

**Benchmark result analysis:**

The latest benchmark results show a significant difference in execution speed between `includes` and `startsWith`. The `includes` test takes about 64,433,226 executions per second (UAString), while the `startsWith` test averages around 14,585,809 executions per second. This indicates that, on average, `startsWith` is faster than `includes`, especially considering the optimization potential in modern browsers.

**Alternatives:**

Some alternatives for string manipulation or comparison could include:

1. **Substring() method**: A more traditional approach to extracting a specific part of a string.
2. **RegExp.test()**: Using regular expressions to match patterns within strings (although, as mentioned earlier, this might be under the hood for both `includes` and `startsWith`).
3. **Regular expression-based solutions**: Implementing custom regex-based solutions using String.prototype.replace or similar methods.

Keep in mind that MeasureThat.net is focused on measuring JavaScript performance, specifically with respect to string manipulation operations like these.

Related benchmarks:

startswith vs includes (exact string) (version: 0)

Comparing performance of: includes vs startsWith

Created: 2 years ago by: Guest

Jump to the latest result

includes

startsWith

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):