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

Benchmark Overview

The benchmark measures the performance of three different approaches to extract a number from a string: splitting, using parseFloat, and using regular expressions.

Options Compared

1. Splitting: This approach involves splitting the input string into substrings separated by whitespace characters (\s) using the split() method. The first substring is then extracted and converted back to a string.
2. parseFloat: This approach uses the parseFloat() function to convert the numeric part of the input string to a floating-point number.
3. Regex: This approach uses regular expressions to extract the numeric part of the input string. Specifically, it matches any characters ([-\\d.]*) that are either digits (\\d), dot (.), or hyphen (-). The matched string is then extracted and converted back to a string.

Pros and Cons

1. Splitting:
   • Pros: Simple and straightforward.
   • Cons: May not work correctly if the input string contains non-whitespace characters before the numeric part, which may lead to incorrect results or errors.
2. parseFloat:
   • Pros: Robust and flexible.
   • Cons: May be slower than other approaches for small numbers due to the overhead of parsing a floating-point number.
3. Regex:
   • Pros: Flexible and powerful, can extract various types of numeric values (e.g., integers, floats).
   • Cons: Can be slower than other approaches for small numbers due to the complexity of regular expressions.

Library Used

None in this specific benchmark, as all tests are performed using built-in JavaScript functions.

Special JS Features or Syntax

There is no special JavaScript feature or syntax used in these tests. The focus is on comparing the performance of different approaches to extract a number from a string.

Other Alternatives

In addition to the three approaches mentioned above, there are other methods to extract numbers from strings, such as:

1. Using parseInt(): Similar to parseFloat(), but uses integer arithmetic instead.
2. Using match() with a more complex regular expression: Can be used to extract more specific types of numeric values (e.g., integers only).
3. Using a custom parsing function: A custom implementation that can handle various edge cases and performance optimizations.

These alternatives may offer better or worse performance depending on the use case, but are not compared in this benchmark.