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

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]; });
for..of
for (var i of array) { array[i]; }
for..in
for (var i in array) { array[i]; }

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

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

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 9 months ago)

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/141.0.0.0 Safari/537.36 Edg/141.0.0.0

Browser/OS: Chrome 141 on Mac OS X 10.15.7

View result in a separate tab

some

11.3M/s

foreach

11.1M/s

for..in

10.8M/s

for

6.1M/s

for..of

1.4M/s

View exact numbers

Test name	Executions per second
✓ some	11,325,799 Ops/sec
foreach	11,082,304 Ops/sec
for..in	10,750,010 Ops/sec
for	6,052,462 Ops/sec
for..of	1,410,142 Ops/sec

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

LLMs can make mistakes. Check important info.

Let's dive into the world of JavaScript microbenchmarks.

**What is being tested?**

MeasureThat.net is testing the performance of different loop constructs in JavaScript:

*   `for` loops
*   `forEach` loops (an array method)
*   `some` loops (an array method)
*   `for..of` loops (a newer, more concise syntax for iterating over arrays)

These loops are used to iterate over an array of 100 elements. The performance test measures how many executions per second each loop can handle.

**Options being compared:**

The test compares the performance of four different loop constructs:

1.  `for` loops
2.  `forEach` loops (an array method)
3.  `some` loops (an array method)
4.  `for..of` loops

Each option has its pros and cons:

*   **For** loops:
    *   Pros: Simple, widely supported, and easy to understand.
    *   Cons: Can be verbose for large iterations, prone to indexing errors.
*   **ForEach** loops (array method):
    *   Pros: Concise, easy to read, and automatically handles array lengths.
    *   Cons: May have performance overhead due to the method call, can be less efficient than traditional `for` loops.
*   **Some** loops (array method):
    *   Pros: Similar to `forEach`, but returns a boolean result indicating whether at least one element matches the condition.
    *   Cons: Also may have performance overhead and is less commonly used.
*   **For..of** loops:
    *   Pros: Concise, easy to read, and automatically handles array lengths. It's also a more modern syntax that many developers are familiar with.
    *   Cons: Still relatively new, some older browsers or environments might not support it.

**Library usage:**

None of the provided test cases use any external libraries. They rely solely on built-in JavaScript functionality.

**Special JS features or syntax:**

There is no mention of special JavaScript features or syntax in this benchmark definition. The tests focus on comparing different loop constructs without introducing any additional complexities.

**Alternative approaches:**

If you were to design an alternative test, you might consider including other loop constructs, such as:

*   `while` loops
*   Recursive functions (for iterating over arrays)
*   Generator functions or async/await (for iterative computations)

Additionally, you could explore testing different array sizes or edge cases (e.g., empty arrays, null or undefined elements) to further validate the performance of each loop construct.

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

Compare loop performance

Comparing performance of: `for vs foreach vs some vs for..of vs for..in`

Created: 4 years ago by: Guest

Go to the latest result

for

foreach

some

for..of

for..in

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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

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

Compare loop performance

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

Created: 4 years ago by: Guest

Go to the latest result

for

foreach

some

for..of

for..in

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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

Related benchmarks

Comparing performance of: `for vs foreach vs some vs for..of vs for..in`