var arr = [];
for (var i = 0; i < 1000; i++) {
arr[i] = i;
}
function someFn(i) {
return (i * 3 * 8 / 1200 * 0.002 / 40 * 0.2);
}
var sumForEach = 0,
sumReduce = 0,
sumMap = 0,
sumFilter = 0,
sumFor = 0;
arr.filter(item => (sumFilter += someFn(item)));
sumReduce = arr.reduce((lastValue, item) => {
return sumReduce += someFn(item);
});
--enable-precise-memory-info
flag.
Test case name | Result |
---|---|
filter | |
reduce |
Test name | Executions per second |
---|---|
filter | 1393.1 Ops/sec |
reduce | 1438.6 Ops/sec |
Let's break down the provided benchmark and its test cases.
Benchmark Overview
The benchmark measures the performance of different JavaScript methods for filtering, mapping, reducing, and summing an array of numbers.
Script Preparation Code
The script preparation code creates an array arr
with 1000 elements, each containing a unique integer value. It also defines a function someFn
that calculates a result based on the input i
. This function is used in multiple test cases to calculate values for filtering and reducing operations.
Html Preparation Code
There is no HTML preparation code provided, which means that this benchmark only tests JavaScript performance without considering any DOM-related aspects.
Test Cases
There are two test cases:
filter()
method with a callback function to filter out elements from the array.reduce()
method with an initial value and a callback function to reduce the array into a single value.Library Usage
There is no explicit library usage in the provided benchmark code, except for built-in JavaScript methods like filter()
, reduce()
, map()
, and basic arithmetic operations. However, some modern browsers may have polyfills or implementations of certain libraries that could potentially affect performance, but this is not explicitly tested in the benchmark.
Special JS Feature/Syntax
There are no special JavaScript features or syntax used in the benchmark code. The test cases only use standard JavaScript methods and operators.
Options Compared
The two main options being compared are:
filter()
method to create a new array with elements that pass a test (in this case, the someFn
function returns a truthy value).reduce()
method to reduce the array into a single value by applying an accumulation function to each element.Pros and Cons of Each Approach
Considerations
When choosing between filter()
and reduce()
, consider the following factors:
reduce()
might be more suitable as it reduces memory allocation overhead.reduce()
can be more efficient due to its single pass through the data.filter()
might provide more flexibility and readability.Alternatives
Other alternatives for filtering or reducing an array include:
map()
and then applying conditional logic to filter out unwanted elements.Keep in mind that these alternatives might introduce additional overhead or complexity, so it's essential to evaluate the specific requirements and constraints of your use case before choosing an approach.