Benchmark: every vs for - MeasureThat.net

Script Preparation code:

var k = 'y';
var a = 'a,b,c,d,e,f,g,h,i,j,k,l,m,n,o,p,r,q,s,t,u,v,w,x,y,z'.split(',');

Tests:

for
for (let i = 0, l = a.length; i < l; ++i) { if (a[i] === k) return false; } return true
every
return a.every(key => { return key !== k; })

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
for
every

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 28 days ago):

LLMs can make mistakes. Check important info.

I'll break down the provided benchmark and its results to explain what's being tested, compared, and their pros and cons.

**Benchmark Overview**

The benchmark compares two approaches for iterating over an array in JavaScript: `for` loops and the `every()` method. The benchmark is designed to measure which approach is faster.

**Script Preparation Code**

The script preparation code creates an array `a` containing a large number of elements (represented by the string `'y'` followed by 26 lowercase letters), and a variable `k` with the value `'y'`. This setup allows for iterating over all elements in the array using both approaches.

**Html Preparation Code**

There is no HTML preparation code provided, which means that the benchmark only focuses on JavaScript performance.

**Benchmark Definitions**

There are two benchmark definitions:

1. **`for` loop**: This approach uses a traditional `for` loop to iterate over the array `a`. The loop variable `i` is initialized with 0, and the length of the array `l` is stored in the variable `l`. The loop increments `i` until it reaches the end of the array.
2. **`every()` method**: This approach uses the `every()` method to iterate over the array `a`. The callback function checks if each element is not equal to `k`.

**Pros and Cons**

Here's a brief analysis of the two approaches:

1. **`for` loop**:
	* Pros: Simple, easy to understand, and works well for small arrays.
	* Cons: Can be slow for large arrays due to the overhead of incrementing the loop variable and checking array indices.
2. **`every()` method**:
	* Pros: More concise and expressive than traditional loops, with a clear focus on predicate functions. This approach is suitable for arrays where most elements are expected to meet the condition (i.e., not equal to `k`).
	* Cons: Can be slower than traditional loops due to the overhead of function calls and potentially more memory allocations.

**Library/Additional Functionality**

None of the benchmark definitions use external libraries or special JavaScript features. The `every()` method is a built-in Array.prototype method, making it easy to compare with the traditional `for` loop.

**Special JS Features/Syntax**

There are no special JavaScript features or syntax used in these benchmark definitions.

**Alternative Approaches**

Other approaches that could be considered for benchmarking array iteration include:

1. **Array.forEach()**: Similar to the `every()` method, but designed specifically for iterating over arrays without returning a value.
2. **Array.prototype.map()`: This approach would involve using `map()` to create a new array of booleans indicating whether each element is not equal to `k`. This could be slower than both the traditional loop and the `every()` method due to the overhead of creating a new array.
3. **Arrow functions**: Instead of using a function expression, you could use an arrow function with the same callback logic as the `every()` method. Arrow functions are generally faster and more concise.

Keep in mind that these alternative approaches would require modifications to the benchmark definitions to accurately measure their performance.

**Other Considerations**

When interpreting the results:

* The `ExecutionsPerSecond` value indicates how many iterations of the loop were executed per second on each browser.
* Chrome 69 is used as the test browser, which might not be representative of other browsers or JavaScript engines. Results may vary on other platforms or with different browsers.

By analyzing these factors and considering alternative approaches, you can gain a better understanding of the trade-offs involved in choosing between traditional loops and `every()` method for array iteration in JavaScript.

Latest run results:

Run details: (Test run date: 6 years ago)

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/69.0.3497.100 Safari/537.36

Browser/OS: Chrome 69 on Windows

View result in a separate tab

Test name	Executions per second
for	142282.0 Ops/sec
every	261288.7 Ops/sec

Related benchmarks:

every vs for (version: 0)

Comparing performance of: for vs every

Created: 6 years ago by: Guest

Jump to the latest result

for

every

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 28 days ago):