var arr = [];
for(let i = 0; i < 10000; i++) {
arr.push(Math.random());
}
let sum = 0;
for(const num of arr) {
sum += num;
}
let sum = 0;
for(let i = 0; i < arr.length; i++) {
sum += arr[i];
}
--enable-precise-memory-info
flag.
Test case name | Result |
---|---|
Iterator for loop | |
Index for loop |
Test name | Executions per second |
---|---|
Iterator for loop | 17979.7 Ops/sec |
Index for loop | 99447.3 Ops/sec |
Let's break down the provided benchmark and explain what's being tested.
Benchmark Overview
The benchmark compares two approaches to iterating over an array: using an iterator (for...of
loop) versus using traditional indexing (for...in
or forEach
loop) with array indices.
Script Preparation Code
The script preparation code creates an empty array arr
and populates it with 10,000 random numbers. This is a simple setup to test the iteration mechanisms.
Html Preparation Code
Since this is a JavaScript microbenchmark, there's no HTML preparation code. The benchmark only focuses on comparing the execution times of different iteration methods in JavaScript.
Library Usage
There isn't any explicit library usage mentioned in the provided code. However, some modern browsers and Node.js versions might use polyfills or built-in libraries for for...of
loops, which could affect the results. Nevertheless, the benchmark focuses on the intrinsic differences between these two iteration methods.
Special JavaScript Features or Syntax
The benchmark uses the following special features:
arr[i]
).forEach
is a built-in method for iterating over arrays.Comparison and Considerations
The benchmark compares the performance of two approaches:
for...of
loop to iterate over the array, which is generally considered more readable and efficient than traditional indexing.forEach
(or a similar construct) to access and iterate over array elements.Pros and Cons
Iterator for Loop:
Pros:
Cons:
Index for Loop:
Pros:
Cons:
for...of
Other Alternatives
Some alternative approaches that could be tested in a benchmark include:
Uint8Array
, Float64Array
) can provide faster iteration times due to their compact memory representation.Keep in mind that the choice of iteration method depends on the specific use case and requirements. The benchmark provides a valuable comparison between two widely used approaches, but exploring other alternatives can help developers make informed decisions about their coding choices.