Benchmark: for vs foreach vs some vs every vs for..of

Script Preparation code:

var array = new Array(100);

Tests:

for
for (var i = 0; i < array.length; i++) { array[i]; }
foreach
array.forEach(function(i) { array[i]; });
some
array.some(function(i) { array[i]; });
every
array.every(function(i) { array[i]; });
for..of
for (var i of array) { array[i]; }

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
for
foreach
some
every
for..of

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 3 years ago)

User agent: Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:84.0) Gecko/20100101 Firefox/84.0

Browser/OS: Firefox 84 on Ubuntu

View result in a separate tab

Test name	Executions per second
for	19863220.0 Ops/sec
foreach	1965947.1 Ops/sec
some	1977950.9 Ops/sec
every	1975583.6 Ops/sec
for..of	136099.1 Ops/sec

Autogenerated LLM Summary (model llama3.2:3b, generated 2 months ago):

LLMs can make mistakes. Check important info.

Let's break down the provided JSON data and explain what's being tested, the different approaches compared, their pros and cons, and other considerations.

**Benchmark Definition**

The benchmark compares the performance of four different loop constructs:

1. `for` loop
2. `forEach` loop (built-in method)
3. `some` loop (built-in method)
4. `every` loop (built-in method)
5. `for...of` loop (newer syntax introduced in ECMAScript 2015)

**Script Preparation Code**

The script preparation code initializes an array with 100 elements, which will be used as the input for the loops.

**Html Preparation Code**

Since there is no HTML preparation code provided, we can assume that only JavaScript code is being executed.

**Individual Test Cases**

Each test case has a benchmark definition in the format of a JavaScript loop. Let's analyze each one:

1. `for` loop: A traditional loop that iterates over an array using a counter variable (`i`) and increments it on each iteration.
2. `forEach` loop: A built-in method that executes a provided function for each element in an array. This loop is optimized by the browser's engine to be more efficient than a traditional `for` loop.
3. `some` loop: Another built-in method that returns `true` as soon as the provided function returns `true` for any element in the array. If the function never returns `true`, it returns `false`. This loop is optimized for situations where you only need to check if at least one element satisfies a condition.
4. `every` loop: A built-in method that returns `true` if the provided function returns `true` for all elements in the array, and `false` otherwise. If the function never returns `true`, it returns `true`.
5. `for...of` loop: A newer syntax introduced in ECMAScript 2015, which allows iterating over an array using a more concise and readable syntax.

**Pros and Cons of Each Approach**

Here's a brief summary:

* `for` loop:
	+ Pros: Easy to understand and implement.
	+ Cons: Can be slower due to the overhead of incrementing the counter variable.
* `forEach` loop:
	+ Pros: Optimized by browsers for efficiency, reduces code duplication.
	+ Cons: Less control over iteration order and index access.
* `some` loop:
	+ Pros: Optimized for early termination, useful when only one element needs to satisfy a condition.
	+ Cons: Returns `false` if no elements satisfy the condition, which might not be the desired behavior.
* `every` loop:
	+ Pros: Useful for checking all elements in an array before returning.
	+ Cons: Can be slower due to the overhead of decrementing the counter variable.
* `for...of` loop:
	+ Pros: More concise and readable syntax, easier to understand for developers familiar with languages like Python or Ruby.
	+ Cons: Less control over iteration order and index access.

**Library Usage**

There are no libraries mentioned in the benchmark definition. All loops use built-in JavaScript methods (`forEach`, `some`, `every`) or traditional `for` loop syntax.

**Special JS Features/Syntax**

The benchmark uses the newer `for...of` loop syntax, which is a relatively new feature introduced in ECMAScript 2015. This syntax provides a more concise and readable way to iterate over arrays, but it's not supported in older browsers or JavaScript engines that don't implement this feature.

**Alternatives**

If you're interested in exploring alternative loop constructs or libraries, here are some options:

* `while` loops: Another traditional loop construct that doesn't use an array index.
* `map()`, `filter()`, and `reduce()` methods: Built-in JavaScript methods for array operations, which can provide more concise code but might be slower than traditional loops.
* Cycles or iterators: Alternative ways to iterate over arrays without using built-in methods.

Keep in mind that the performance differences between these approaches will depend on the specific use case, browser engine, and JavaScript version.

Related benchmarks:

for vs foreach vs some vs every vs for..of (version: 0)

Compare loop performance

Comparing performance of: for vs foreach vs some vs every vs for..of

Created: 3 years ago by: Guest

Jump to the latest result

for

foreach

some

every

for..of

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 2 months ago):