Benchmark: array math.max vs for loop variants

array math.max vs for loop variants (version: 0)

compare finding the maximum value with math.max using .apply & using the spread (...) operator, vs a basic for loop with an if statement, a basic foor loop using length caching, a reversed iterate basic loop, & finally a for-of loop

Comparing performance of: Math.max.apply vs Math.max with spread vs basic for loop vs for loop length caching vs for loop reverse vs for-of loop

Created: one year ago by: Guest

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Script Preparation code:

var arr = [];
var max = -Infinity;
for (i = 0; i < 4096; i++) { 
  arr.push(Math.random() * i);
}

Tests:

Math.max.apply
max = Math.max.apply(Math, arr);
Math.max with spread
max = Math.max(...arr);
basic for loop
for (let i = 0; i < arr.length; i++) { if (arr[i] > max) { max = arr[i]; } }
for loop length caching
for (let i = 0, len = arr.length; i < len; i++) { if (arr[i] > max) { max = arr[i]; } }
for loop reverse
for (let i = arr.length - 1; i >= 0; i--) { if (arr[i] > max) { max = arr[i]; } }
for-of loop
for (const value of arr) { if (value > max) { max = value; } }

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Math.max.apply
Math.max with spread
basic for loop
for loop length caching
for loop reverse
for-of loop

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: one year ago)

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:134.0) Gecko/20100101 Firefox/134.0

Browser/OS: Firefox 134 on Windows

View result in a separate tab

Test name	Executions per second
Math.max.apply	52504.6 Ops/sec
Math.max with spread	52354.1 Ops/sec
basic for loop	144585.6 Ops/sec
for loop length caching	155074.0 Ops/sec
for loop reverse	144456.4 Ops/sec
for-of loop	21305.4 Ops/sec

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

LLMs can make mistakes. Check important info.

Let's break down the benchmark and its test cases.

**Benchmark Description**

The benchmark compares the performance of different ways to find the maximum value in an array:

1. Using `Math.max.apply(Math, arr)`
2. Using the spread operator (`...arr`)
3. A basic for loop with an if statement
4. A basic for loop with length caching (to avoid re-accessing `arr.length` on each iteration)
5. A reversed iterate basic loop
6. A for-of loop

**Pros and Cons of Different Approaches**

1. **Math.max.apply(Math, arr)**:
	* Pros: concise and readable
	* Cons: may be slower due to the overhead of applying a function to an array
2. **Math.max(...arr)** (using spread operator):
	* Pros: similar performance to `Math.max.apply`, but more concise and modern-looking
	* Cons: requires JavaScript 2015 or later syntax
3. **Basic for loop with if statement**:
	* Pros: simple and familiar, no additional dependencies required
	* Cons: may be slower due to the overhead of repeated array lookups and comparisons
4. **Basic for loop with length caching**:
	* Pros: can improve performance by avoiding repeated `arr.length` lookups
	* Cons: slightly more complex code, requires understanding of how caching works
5. **Reversed iterate basic loop**:
	* Pros: can be optimized for specific use cases (e.g., finding the maximum value in a sorted array)
	* Cons: may be slower or less readable than other approaches due to the need to reverse the iteration order
6. **For-of loop**:
	* Pros: modern and concise, allows for iterating over arrays without indexing
	* Cons: may not be familiar to all developers, may have performance overhead due to the iterator object creation

**Library Usage**

None of the test cases use external libraries.

**Special JavaScript Features or Syntax**

1. **Spread operator (`...arr`)**: used in tests 2 and 3 to pass an array as individual arguments to `Math.max`.
2. **For-of loop**: used in test case 6, which provides a concise way to iterate over arrays without indexing.
3. **Length caching**: used in test case 4, where the value of `arr.length` is stored in a variable (`len`) and reused on each iteration.

**Alternatives**

If you wanted to write this benchmark using a different language or framework, some alternatives could be:

* Using Python with its built-in `max` function and list comprehensions
* Using C++ with its standard library and iterator classes
* Using Java with its `Collections.max` method and enhanced for loops

However, JavaScript is well-suited for this benchmark due to its dynamic nature, ease of use, and wide adoption.

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