Benchmark: every vs for loop large arrays not empty

Script Preparation code:

window.a = Array(1_000_000).fill(null).flatMap(() => [1, 2, 3, 4, 5]);
window.b = [1, 2, 4, 5, 3, 5];

Tests:

every
a.every(x => b.some(y => x === y));
for loop
for (let i = 0, l = a.length; i < l; i++) { if (!b.some(y => a[i] === y)) { break; } }

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
every
for loop

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 2 years ago)

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/124.0.0.0 Safari/537.36

Browser/OS: Chrome 124 on Mac OS X 10.15.7

View result in a separate tab

Test name	Executions per second
every	3.7 Ops/sec
for loop	1.0 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 on MeasureThat.net.

**What is being tested?**

The provided JSON represents two benchmark test cases:

1. `every`: This test case checks the performance of the `Array.prototype.every()` method, which returns `true` if all elements in the array pass a given test.
2. `for loop`: This test case checks the performance of a traditional `for` loop iteration against an array.

**Options compared**

In both test cases, two approaches are being compared:

1. **Built-in `every()` method**: The built-in JavaScript method for checking if all elements in an array pass a certain condition.
2. **Manual `for` loop iteration**: A traditional `for` loop that iterates over the array elements to check if any of them pass a certain condition.

**Pros and Cons**

Here's a brief summary of each approach:

1. **Built-in `every()` method**:
	* Pros:
		+ Shorter code
		+ Less prone to errors (as it's a built-in method)
		+ Optimized by the JavaScript engine
	* Cons:
		+ May have performance overhead due to dynamic typing and method call overhead
		+ Limited control over iteration and condition checking
2. **Manual `for` loop iteration**:
	* Pros:
		+ More control over iteration and condition checking
		+ Can be optimized for specific use cases (e.g., caching results or using SIMD instructions)
	* Cons:
		+ Longer code
		+ Prone to errors if not implemented carefully
		+ May incur performance overhead due to explicit iteration and condition checks

**Library and special JS feature**

In the `every` test case, no specific library is mentioned. However, it's worth noting that some libraries (e.g., Lodash) provide optimized implementations of the `every()` method.

The `for loop` test case uses a traditional `for` loop, which does not rely on any special JavaScript features.

**Other alternatives**

If you want to optimize your code further, you can consider alternative approaches, such as:

1. **Using `Array.prototype.some()`**: Instead of `every()`, you could use `some()` and negate the result using the logical NOT operator (`!`).
2. **Caching intermediate results**: If the condition checking is expensive or memory-intensive, consider caching intermediate results to avoid recalculating them.
3. **Using SIMD instructions**: If your condition checks involve simple arithmetic operations (e.g., `x === y`), you can use SIMD (Single Instruction, Multiple Data) instructions to perform multiple iterations simultaneously.

Keep in mind that the best approach depends on your specific use case and performance requirements.

**Benchmark preparation code**

The provided JavaScript code creates two arrays:

1. `a`: A large array with 1,000,000 elements, filled with null values and then flattened into an array of individual numbers.
2. `b`: An array containing a mix of duplicate and unique values.

These arrays are used to test the performance of both the built-in `every()` method and the manual `for` loop iteration approach.

Related benchmarks:

every vs for loop large arrays not empty (version: 1)

Comparing performance of: every vs for loop

Created: 2 years ago by: Registered User

Jump to the latest result

every

for loop

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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