var array = new Array(1714176);
for (var i = 0; i < array.length; i++) {
array[i];
}
array.forEach(function(i) {
array[i];
});
array.some(function(i) {
array[i];
});
for (var i of array) {
array[i];
}
--enable-precise-memory-info
flag.
Test case name | Result |
---|---|
for | |
foreach | |
some | |
for..of |
Test name | Executions per second |
---|---|
for | 4.1 Ops/sec |
foreach | 224.6 Ops/sec |
some | 221.2 Ops/sec |
for..of | 5.4 Ops/sec |
The provided JSON represents a JavaScript microbenchmarking test on the MeasureThat.net website. The benchmark compares the performance of four different loop structures: traditional for
, forEach
, some
, and the newer for..of
syntax.
Let's break down each option:
for
: This is the most basic type of loop, where the index variable i
is explicitly declared and incremented. The pros of this approach are:forEach
: This loop structure iterates over an array using a callback function that is applied to each element. The pros of this approach are:some
: This loop structure returns true
as soon as it finds an element that passes a test, short-circuiting further iterations. The pros of this approach are:for..of
: This newer syntax uses the for...of
loop to iterate over an array, which is similar to forEach
. However, it provides a more concise and expressive way of writing loops. The pros of this approach are:for
.
The cons are:Now, let's analyze the latest benchmark results:
The results show that:
forEach
performs best with an average execution rate of 224.59 executions per second.some
is close behind, with an average execution rate of 221.20 executions per second.for..of
and traditional for
perform significantly slower, with average execution rates of 5.38 and 4.15 executions per second, respectively.The reasons for these differences are:
forEach
likely incurs additional overhead due to the callback function's execution.some
stops iterating early, which is beneficial for large arrays.for..of
and traditional for
may have slower performance due to their syntax and parsing overhead.Other alternatives that are not included in this benchmark but worth mentioning include:
forEach
or some
loops, providing a concise way of writing callbacks.for...of
loops, allowing for more expressive and efficient iteration over arrays.Overall, the results suggest that forEach
is the most performant option, followed closely by some
. The newer for..of
syntax and traditional for
are slower due to their syntax and parsing overhead.