function map(arr, callback) {
const _length = arr.length;
const result = new Array(_length);
for (let i = 0; i < _length; i++) {
result[i] = callback(arr[i], i, arr);
}
return result;
}
function arrayWithNoLength(arr, callback) {
const result = [];
for (let i = 0; i < arr.length; i++) {
result.push(callback(arr[i], i, arr));
}
return result;
}
function mapHowArrayMethod(arr, callback) {
return arr.map(callback);
}
map(new Array(1000000).fill(1000), (num) => num * 2);
arrayWithNoLength(new Array(1000000).fill(1000), (num) => num * 2);
mapHowArrayMethod(new Array(1000000).fill(1000), (num) => num * 2);
--enable-precise-memory-info
flag.
Test case name | Result |
---|---|
MAP | |
ARRAY_WITH_NO_LENGTH | |
MAP_HOW_ARRAY_METHOD |
Test name | Executions per second |
---|---|
MAP | 141.3 Ops/sec |
ARRAY_WITH_NO_LENGTH | 63.4 Ops/sec |
MAP_HOW_ARRAY_METHOD | 83.9 Ops/sec |
Let's break down the provided JSON and benchmark setup.
Benchmark Definition
The benchmark is designed to compare three different approaches to implementing the map
function in JavaScript:
map
function that takes an array, callback function, and returns a new array with the results of applying the callback to each element.map
method, which is a part of the JavaScript language.Options Compared
The benchmark compares the performance of these three approaches:
Pros and Cons
Library and Purpose
None of the provided implementations use any external libraries. They are custom implementations of the map
function.
Special JS Feature or Syntax
The benchmark uses a special JavaScript feature: array methods (map
, forEach
, etc.). These methods were introduced in ECMAScript 2015 (ES6) and provide a concise way to iterate over arrays.
Other Alternatives
If you're looking for alternative implementations of the map
function, you could consider:
Symbol.iterator
and next()
methods.Keep in mind that these alternatives may have different performance characteristics and use cases compared to the benchmarked implementations.