Overview of the Benchmark

The provided benchmark measures the performance of different methods for rounding and formatting decimal numbers in JavaScript. The test cases compare the execution time of various functions, including toFixed, toPrecision, Math.round, Math.floor fast (a shorthand for ~~(someFloat * 10000) / 10000), Math.trunc, and a library-based function using Numeral.js.

Methods Compared

1. toFixed(4): Rounds the number to 4 decimal places.
   • Pros: Simple, straightforward implementation.
   • Cons: May not be suitable for all precision requirements.
2. toPrecision(4).toString(): Formats the number as a string with 4 significant digits.
   • Pros: More flexible than toFixed, can handle different precision requirements.
   • Cons: Requires an extra conversion to string, may impact performance.
3. (Math.round(someFloat * 10000) / 10000).toString(): Rounds the number using Math.round and then divides by 10000.
   • Pros: Simple, straightforward implementation.
   • Cons: May not be as accurate as other methods, especially for large numbers.
4. Math.floor fast (shorthand for ~~(someFloat * 10000) / 10000): Rounds the number using the bitwise NOT operator (~) to truncate it.
   • Pros: Very fast implementation, suitable for high-performance applications.
   • Cons: May not be suitable for all precision requirements, can produce rounding errors.
5. Math.trunc: Rounds the number to the nearest integer.
   • Pros: Fast implementation, suitable for high-performance applications.
   • Cons: May not be suitable for decimal numbers.
6. numeral(someFloat).format('0.0000') (using Numeral.js): Formats the number as a string with 6 decimal places using the Numeral.js library.
   • Pros: More flexible than other methods, can handle different precision requirements.
   • Cons: Requires an external library, may impact performance.

Library Used

The numeraljs library is used in one of the test cases to format the number as a string with 6 decimal places. Numeral.js provides a convenient and flexible way to work with numbers, but it does require an external library.

Special JavaScript Feature/Syntax

None mentioned in this benchmark.

Other Alternatives

Other alternatives for rounding and formatting decimal numbers in JavaScript include:

• Using the Number.EPSILON constant to determine the smallest representable floating-point value.
• Implementing a custom rounding algorithm using bitwise operations, such as ~~ or << 1.
• Using a library like Moment.js or Luxon to work with dates and numbers.

Benchmark Results

The benchmark results show that the execution times vary depending on the method used. The fastest methods are Math.floor fast and Math.trunc, while toFixed(4) and toPrecision(4).toString() are slower due to the extra conversions required. The Numeral.js implementation is also slower than the native JavaScript implementations.

Note that these results may vary depending on the specific browser, platform, and hardware used for running the benchmark.