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;

Tests:

for
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; } });
some
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; } }

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
for
foreach
some
for..of

Fastest: N/A

Slowest: N/A

Latest run results:

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

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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.

Related benchmarks:

check if variable in array has state (for vs foreach vs some vs for..of) (version: 0)

Compare loop performance

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

Created: 5 years ago by: Guest

Jump to the latest result

for

foreach

some

for..of

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

No previous run results

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