Benchmark: Totara Learning Solutions JavaScript

Script Preparation code:

var a = [1, 2, 3, 4, 5, 6, 5, 4];
var b = [6, 8, 2, 7, 6, 1, 4, 3];

function usingForEach(l1, l2) {
    let u = []// Creates a new empty array.
    l1.forEach(function(i) { //loops through the first array input.
        if (u.indexOf(i) < 0) //If 'i' is not in the new array, it is pushed into the new array.
            u.push(i);
    });
    l2.forEach(function(j) { //loops through the second array input.
        if (u.indexOf(j) < 0) //If 'j' is not in the new array, it is pushed into the new array.
            u.push(j);
    });
    return u;
};

function usingSet(l1, l2) {
    let u = l1.concat(l2); // Joins the l1 and l2 arrays together using concatenation.
    return [...new Set(u)]; // Array is converted into a 'Set' in order to remove duplicates, then is converted back into an array using the spread operator.
};

Tests:

forEach Test
var test1 = usingForEach(a,b);
usingSet Test
var test2 = usingSet(a,b);

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
forEach Test
usingSet Test

Fastest: N/A

Slowest: N/A

Latest run results:

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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 options.

The provided JSON represents a JavaScript microbenchmark test case on MeasureThat.net, which compares the performance of two approaches: using `forEach` loops and concatenating arrays with `Set`.

**Benchmark Description**

The benchmark tests the speed of two functions:

1. `usingForEach`: This function uses traditional `forEach` loops to create a new array that contains elements from both input arrays only if they are not already present in the new array.
2. `usingSet`: This function concatenates the two input arrays using `concat()` and then converts the resulting array to an array with unique values using `Set`. The `Set` object automatically removes duplicates.

**Options Compared**

The benchmark compares the performance of these two approaches:

1. **Traditional `forEach` loops**: This approach uses the `forEach` method on both input arrays, which can lead to slower performance due to the overhead of the loop and potential issues with array iteration.
2. **Concatenation with `Set`**: This approach concatenates the two arrays using `concat()` and then converts the resulting array to an array with unique values using `Set`. While this approach may seem efficient, it can lead to slower performance if the input arrays are large due to the overhead of creating a new array and converting it to a set.

**Pros and Cons**

Here's a summary of the pros and cons of each approach:

* **Traditional `forEach` loops**: Pros:
	+ Easy to understand and implement.
	+ Can be efficient for small arrays or simple use cases.
Cons:
	+ May lead to slower performance due to loop overhead.
	+ Potential issues with array iteration (e.g., iterating over an empty array).
* **Concatenation with `Set`**: Pros:
	+ Can eliminate duplicates from the input arrays efficiently.
	+ May be faster for large input arrays due to the set data structure.
Cons:
	+ Creates a new array that contains all elements from both input arrays, which can lead to slower performance for small arrays or simple use cases.
	+ Requires creating an intermediate array and converting it to a set.

**Library and Special JS Features**

The benchmark uses the following libraries:

* `Set`: A built-in JavaScript object that removes duplicates from an array.

There are no special JavaScript features mentioned in this benchmark.

**Other Considerations**

When dealing with large input arrays, other factors can affect performance, such as:

* Memory allocation and deallocation for large arrays
* Cache efficiency due to the size of the arrays
* The specific implementation details of the `forEach` method on both arrays

Keep in mind that these are general considerations and may not apply directly to this specific benchmark.

**Alternatives**

If you're interested in exploring alternative approaches, here are a few options:

1. **Using `filter()` instead of `Set`:** Instead of using `Set`, you could use the `filter()` method on the resulting array to remove duplicates.
2. **Using `map()` and `reduce()`**: You could also use the `map()` method to create an array with unique elements and then reduce it using a callback function.
3. **Using `reduce()` without filtering:** If you don't need to eliminate duplicates, you can use the `reduce()` method directly on one of the input arrays.

Keep in mind that these alternatives may have different trade-offs in terms of performance and code complexity.

Related benchmarks:

Totara Learning Solutions JavaScript (version: 0)

Benchmarking the speed/performance between using forEach loops and concat() + Set()

Comparing performance of: forEach Test vs usingSet Test

Created: 3 years ago by: Guest

Jump to the latest result

forEach Test

usingSet Test

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):