var array = new Array(100);for (var i = 0; i < array.length; i++) { array[i] = 1;}array.forEach(function(i) { array[i] = 1;});array.some(function(i) { array[i] = 1;});for (var i of array) { array[i] = 1;}--enable-precise-memory-info flag.
| Test case name | Result |
|---|---|
| for | |
| foreach | |
| some | |
| for..of |
| Test name | Executions per second |
|---|---|
| for | 911707.6 Ops/sec |
| foreach | 1147704.1 Ops/sec |
| some | 1146486.5 Ops/sec |
| for..of | 1021717.9 Ops/sec |
Let's break down the benchmark and explain what's being tested.
Benchmark Definition
The benchmark is designed to compare the performance of different loop iteration methods in JavaScript: for, forEach, some, and for...of. The benchmark creates an array with 100 elements and measures how many iterations each loop method performs per second.
Loop Iteration Methods
Here's a brief explanation of each loop iteration method:
for: This is the traditional loop syntax, where you declare a variable (in this case, i) and increment it manually to iterate over the array.forEach: This method executes a callback function for each element in an array. In this benchmark, the callback function simply assigns the value 1 to each element.some: Similar to forEach, but returns true as soon as the condition inside the callback function is met (in this case, always true since we're assigning a value). The loop continues iterating over the array until some returns false.for...of: This is a newer loop syntax introduced in ECMAScript 2015. It allows you to iterate over arrays using a simple for-each syntax.Pros and Cons of Each Approach
Here's a brief summary of the pros and cons of each approach:
for:forEach:some:forEach, but can be faster since it returns early.for...of:Library Usage
None of the loop iteration methods use any external libraries. The benchmark relies solely on built-in JavaScript features.
Special JS Features or Syntax
This benchmark uses modern JavaScript features:
var is used for variable declaration (not let or const, which are more modern alternatives).Array.prototype.forEach and Array.prototype.some are used to execute the callback functions.for...of loop syntax is used to iterate over the array.Other Alternatives
If you're interested in exploring alternative loop iteration methods, here are a few options:
while: A traditional loop syntax that requires manual index management.Array.prototype.forEach with a custom callback function (not using the some method).Keep in mind that these alternatives may not be as efficient or modern as the methods used in this benchmark.
