Benchmark: Sum with for and reduce

Script Preparation code:

var arr = [];

for(var i = 0; i<1000*1000;i++){arr.push(Math.random());}

function sumFor(arr){
  	let sum = 0;
	for(var i = 0;i<arr.length;i++){
		sum += arr[i];
	}
  return sum;
}

function sumReduce(arr){
	return arr.reduce((a,b)=>a+b,0);
}

Tests:

Sum with for
var x = sumFor(arr);
Sum with Reduce
var y = sumReduce(arr);

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Sum with for
Sum with Reduce

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 break down the provided benchmark and its test cases.

**Benchmark Definition JSON**

The benchmark definition provides two JavaScript functions: `sumFor` and `sumReduce`. Both functions are designed to calculate the sum of an array of random numbers. The main difference between the two is how they implement the summation:

*   **sumFor**: This function uses a traditional for loop to iterate over the array and add each element to a running total.
*   **sumReduce**: This function utilizes the Array.prototype.reduce() method, which applies a callback function to each element in the array, accumulating a result.

**Options Compared**

The benchmark compares two different approaches to calculate the sum of an array:

1.  **Manual Loop (sumFor)**: Uses a traditional for loop to iterate over the array.
2.  **Built-in Reduce Method (sumReduce)**: Leverages the Array.prototype.reduce() method, which provides a concise and efficient way to perform cumulative computations.

**Pros and Cons**

*   **Manual Loop (sumFor)**:
    *   Pros:
        +   Easy to understand and implement for developers familiar with traditional looping.
        +   Can be useful for educational purposes or when specific control over iteration is required.
    *   Cons:
        +   More verbose and less readable compared to the reduce method.
        +   Potential performance overhead due to the explicit loop.
*   **Built-in Reduce Method (sumReduce)**:
    +   Pros:
        -   Concise and readable implementation.
        -   Highly optimized by the browser's engine, resulting in better performance.
    *   Cons:
        -   May be less familiar or harder to understand for developers without experience with Array.prototype methods.

**Library/Function Used**

The `Array.prototype.reduce()` method is a built-in JavaScript function used to apply a callback function to each element of an array, accumulating a result. It's commonly used in many programming languages and libraries.

**Special JS Features/Syntax**

There are no special JavaScript features or syntax explicitly mentioned in the benchmark definition. However, the use of `let` for variable declarations is a modern JavaScript feature introduced in ECMAScript 2015 (ES6).

**Alternatives**

Other alternatives to implement summing functionality include:

*   Using `forEach()` instead of a loop: `arr.forEach((element) => { sum += element; });`
*   Using `reduce()` with an initial value: `arr.reduce((sum, element) => sum + element, 0)`
*   Using libraries like Lodash (for its `sumby` function)
*   Implementing the sum using a different data structure, such as a Map or a Set

Related benchmarks:

Sum with for and reduce (version: 0)

Comparing performance of: Sum with for vs Sum with Reduce

Created: 6 years ago by: Guest

Jump to the latest result

Sum with for

Sum with Reduce

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):