Benchmark: string-substring-vs-slice

Script Preparation code:

var str = Math.random().toString(36).substring(10)

Tests:

string-substring
str.charAt(0).toUpperCase() + str.substring(1)
string-slice
str.charAt(0).toUpperCase() + str.slice(1)

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
string-substring
string-slice

Fastest: N/A

Slowest: N/A

Latest run results:

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

LLMs can make mistakes. Check important info.

I'd be happy to help explain the JavaScript microbenchmark on MeasureThat.net.

**What is being tested?**

The provided benchmark measures the performance of two approaches for extracting the first character and substring (excluding the first character) from a randomly generated string. The string is created using `Math.random().toString(36).substring(10)`.

**Options compared:**

There are two options being compared:

1. **charAt() + substring()**: This approach uses the `charAt()` method to get the first character of the string and then concatenates it with the result of calling `substring()` on the same string, starting from index 1.
2. **slice() + substring()**: This approach uses the `slice()` method to extract a substring from the original string, excluding the first character.

**Pros and Cons:**

* **charAt() + substring()**:
	+ Pros: Simple and intuitive.
	+ Cons: May incur overhead due to the use of `concat()` when concatenating strings.
* **slice() + substring()**:
	+ Pros: Avoids the potential overhead of `concat()` and may be more efficient for larger strings.
	+ Cons: Requires a bit more thinking, as it's not immediately clear what's happening.

In terms of performance, both approaches have their trade-offs. The `charAt() + substring()` approach is simpler to understand but might incur some additional overhead due to the use of concatenation. On the other hand, the `slice() + substring()` approach avoids this potential overhead and may be more efficient for larger strings.

**Library usage:**

There are no external libraries being used in these benchmarks.

**Special JavaScript features or syntax:**

The benchmark uses a few special features:

* **`Math.random().toString(36)`**: This creates a random string of 10 characters using base 36 encoding. The `toString()` method is called with an argument to specify the radix (base) as 36, which results in a hexadecimal-like string.
* **`slice()` and `substring()`**: These are methods of the String object that extract substrings from strings. `slice()` takes two arguments: the start index and the length of the substring to extract.

**Other alternatives:**

If you wanted to use alternative approaches for extracting the first character and substring, some options might include:

* Using `substr()` instead of `charAt() + substring()` or `slice()`.
* Using a regular expression with capturing groups instead of `charAt()` and `substring()` or `slice()`.
* Using a library like Lodash's `getFirst` and `dropRight` methods.

Keep in mind that the performance characteristics of these alternatives would depend on the specific use case and requirements.

Related benchmarks:

string-substring-vs-slice (version: 0)

Comparing performance of: string-substring vs string-slice

Created: 5 years ago by: Guest

Jump to the latest result

string-substring

string-slice

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):