var someFloat = 0.123456789;
someFloat.toFixed(4)
someFloat.toPrecision(4)
(someFloat*10000|0)/10000
--enable-precise-memory-info
flag.
Test case name | Result |
---|---|
toFixed(4) | |
toPrecision(4).toString() | |
(Math.round(*10000)/10000).toString() |
Test name | Executions per second |
---|---|
toFixed(4) | 3784979.0 Ops/sec |
toPrecision(4).toString() | 4191842.8 Ops/sec |
(Math.round(*10000)/10000).toString() | 10103409.0 Ops/sec |
Let's dive into the explanation of the provided benchmark.
What is tested on the provided JSON?
The benchmark tests three different approaches to round or format a floating-point number:
toFixed(4)
: This method returns a string representation of the float, rounded to 4 decimal places.toPrecision(4).toString()
: This method returns a string representation of the float, with a precision of 4 decimal places. The toPrecision()
method is a non-standard property that was introduced in older versions of JavaScript engines.(someFloat*10000|0)/10000
(also known as bitwise rounding): This method uses a bitwise operation to round the float to 4 decimal places.Options compared
The benchmark compares these three approaches, allowing users to see which one is faster and more efficient in terms of CPU cycles.
Pros and Cons of each approach
toFixed(4)
:toPrecision(4).toString()
: (Note: This property was introduced in older JavaScript versions and is not widely supported.)(someFloat*10000|0)/10000
(bitwise rounding):Other considerations
The benchmark also considers the device platform, operating system, and browser version, which can affect the performance of each approach. It's essential to note that the results might vary depending on these factors.
Libraries used
None of the provided benchmarks use external libraries. The script preparation code includes a simple variable someFloat
with a value of 0.123456789
, and no library functions are called in any of the test cases.
Special JavaScript features or syntax
The only special feature mentioned is bitwise rounding, which uses the bitwise OR operator (|
) to perform a round-to-nearest-even operation on the float. This technique is used in some programming languages, but it's not a standard JavaScript feature.
Alternatives
If users want to explore alternative approaches to rounding floats, they can try:
Number.EPSILON
and arithmetic operations to implement their own rounding algorithm.Keep in mind that the best approach will depend on specific use cases and performance requirements.