Benchmark: check if variable in array has state (for vs foreach vs some vs for..of)

Script Preparation code:

var array = new Array(100);
for (let i = 0; i < array.length; i++) {
 array[i] = 0; 
}

array[50] = 1;

​x
 
var array = new Array(100);for (let i = 0; i < array.length; i++) { array[i] = 0; }​array[50] = 1;

Tests:

for

let isOne = false;

for (var i = 0; i < array.length; i++) {
  if (array[i] === 1) {
    isOne = true;
    break;
  }
}

 
let isOne = false;​for (var i = 0; i < array.length; i++) {  if (array[i] === 1) {    isOne = true;    break;  }}

foreach

let isOne = false;

array.forEach(function(i) {
  if (array[i] === 1) {
    isOne = true;
  }
});

 
let isOne = false;​array.forEach(function(i) {  if (array[i] === 1) {    isOne = true;  }});

some

let isOne = array.some(function(i) {
  return array === 1;
});

 
let isOne = array.some(function(i) {  return array === 1;});

for..of

let isOne = false;

for (var i of array) {
  if (array[i] === 1) {
    isOne = true;
  }
}

 
let isOne = false;​for (var i of array) {  if (array[i] === 1) {    isOne = true;  }}

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Experimental features:

Memory measurements supported only in Chrome.
For precise memory measurements Chrome must be launched with --enable-precise-memory-info flag.
More information: Monitoring JavaScript Memory

Test case name	Result
for
foreach
some
for..of

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 4 years ago)

User agent: Mozilla/5.0 (X11; Linux x86_64; rv:81.0) Gecko/20100101 Firefox/81.0

Browser/OS: Firefox 81 on Linux

View result in a separate tab

Test name	Executions per second
for	2517302.8 Ops/sec
foreach	1361929.1 Ops/sec
some	2194339.8 Ops/sec
for..of	1021862.2 Ops/sec

Autogenerated LLM Summary (model llama3.2:3b, generated 6 months ago):

Let's dive into the JavaScript microbenchmarking test case.

Overview

The test measures the performance of four different loop constructs: for, forEach, some, and for...of. The goal is to determine which construct is the most efficient for a specific use case: checking if an element in an array has a certain state (in this case, whether it's equal to 1).

Loop Constructs Compared

for: A traditional loop that uses a counter variable and an explicit termination condition.
forEach: A method that iterates over the elements of an array, providing access to each element in its context.
some: A method that returns true if at least one element in an array satisfies a provided testing function.
for...of: A newer loop construct that uses a for loop with a const or let declaration and the of keyword to specify the iterable.

Pros and Cons of Each Approach

for:
- Pros: Simple, efficient, and widely supported.
- Cons: Can be verbose for complex loops, and counter variables can lead to bugs if not managed properly.
forEach:
- Pros: Concise, easy to read, and provides a clear indication of the intent behind the loop.
- Cons: May incur overhead due to method invocation, and can be less efficient than traditional for loops for large arrays.
some:
- Pros: Can be used as a shortcut for simple iteration and early exit conditions.
- Cons: May be slower than traditional for loops due to the method invocation overhead, and its behavior is not immediately obvious to all developers.
for...of:
- Pros: Concise, readable, and provides a clear indication of the intent behind the loop.
- Cons: Limited support in older browsers and environments, and may incur overhead due to the new syntax.

Library Used

In this test case, none of the loops use an external library. However, the forEach loop uses the built-in Array.prototype.forEach() method, which is a part of the ECMAScript standard.

Special JS Feature or Syntax

None of the test cases use any special JavaScript features or syntax beyond what's mentioned above.

LLMs can make mistakes. Check important info.

Let's dive into the JavaScript microbenchmarking test case.

**Overview**

The test measures the performance of four different loop constructs: `for`, `forEach`, `some`, and `for...of`. The goal is to determine which construct is the most efficient for a specific use case: checking if an element in an array has a certain state (in this case, whether it's equal to 1).

**Loop Constructs Compared**

1. **`for`**: A traditional loop that uses a counter variable and an explicit termination condition.
2. **`forEach`**: A method that iterates over the elements of an array, providing access to each element in its context.
3. **`some`**: A method that returns `true` if at least one element in an array satisfies a provided testing function.
4. **`for...of`**: A newer loop construct that uses a `for` loop with a `const` or `let` declaration and the `of` keyword to specify the iterable.

**Pros and Cons of Each Approach**

1. **`for`**:
	* Pros: Simple, efficient, and widely supported.
	* Cons: Can be verbose for complex loops, and counter variables can lead to bugs if not managed properly.
2. **`forEach`**:
	* Pros: Concise, easy to read, and provides a clear indication of the intent behind the loop.
	* Cons: May incur overhead due to method invocation, and can be less efficient than traditional `for` loops for large arrays.
3. **`some`**:
	* Pros: Can be used as a shortcut for simple iteration and early exit conditions.
	* Cons: May be slower than traditional `for` loops due to the method invocation overhead, and its behavior is not immediately obvious to all developers.
4. **`for...of`**:
	* Pros: Concise, readable, and provides a clear indication of the intent behind the loop.
	* Cons: Limited support in older browsers and environments, and may incur overhead due to the new syntax.

**Library Used**

In this test case, none of the loops use an external library. However, the `forEach` loop uses the built-in `Array.prototype.forEach()` method, which is a part of the ECMAScript standard.

**Special JS Feature or Syntax**

None of the test cases use any special JavaScript features or syntax beyond what's mentioned above.

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Created: 4 years ago by: Guest

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