var N = 1000000
var sum = 0
for(let i = 0; i < N; i++) {
if (!!(i & 0xFF)) sum++
}
var sum = 0
for(let i = 0; i < N; i++) {
if((i & 0xFF) !== 0) sum++
}
var sum = 0
for(let i = 0; i < N; i++) {
if(i & 0xFF) sum++
}
--enable-precise-memory-info
flag.
Test case name | Result |
---|---|
!! | |
!== 0 | |
direct |
Test name | Executions per second |
---|---|
!! | 1526.3 Ops/sec |
!== 0 | 1525.4 Ops/sec |
direct | 1539.4 Ops/sec |
Let's break down the provided benchmark and explain what is being tested.
Benchmark Overview
The benchmark measures the performance of different approaches for incrementing a variable within a loop. The three test cases use the !!
operator, strict inequality (!== 0
), and direct bit manipulation to compare the value of a variable with zero or not-zero.
Test Cases
var sum = 0for(let i = 0; i < N; i++) { if (!!(i & 0xFF)) sum++ }
!!
) to convert a boolean value to a number (1 or 0).var sum = 0for(let i = 0; i < N; i++) { if((i & 0xFF) !== 0) sum++ }
!==
) to check if a value is not equal to zero.var sum = 0for(let i = 0; i < N; i++) { if(i & 0xFF) sum++ }
Library and Special Features
None of the test cases use any libraries. However, they do utilize special JavaScript features:
&
, !=
) to manipulate bits.i
).Pros and Cons
Here's a brief summary of the pros and cons of each approach:
!!
operator, may introduce additional overhead.Other Alternatives
If you're looking for alternative approaches, consider:
Number
function with a radix argument (e.g., Number(i) === 0
) instead of !!
.Boolean
value directly (i
as a boolean).Keep in mind that these alternatives may not be relevant depending on your specific use case and performance requirements.
In summary, the benchmark compares three different approaches for incrementing a variable within a loop. The !!
operator is compared with strict inequality (!== 0
) and direct bit manipulation. Each approach has its pros and cons, and alternative solutions can be considered based on specific use cases and performance requirements.