Benchmark: Set difference vs set difference with union

Script Preparation code:

var from = new Set();
var match1 = new Set();
var match2 = new Set();
var match3 = new Set();
var mismatch1 = new Set();
var mismatch2 = new Set();
var mismatch3 = new Set();

for (let i = 0; i < 1000; i++) {
    from.add(i);
    match1.add(i);
    match2.add(i);
    match3.add(i);
    mismatch1.add(1000 + i);
    mismatch2.add(2000 + i);
    mismatch3.add(3000 + i);
}

function setsUnion(sets) {
    if (sets.length === 1) {
        return sets[0];
    }

    const result = new Set();
    for (let i = 0; i < sets.length; i++) {
        for (const value of sets[i]) {
            result.add(value);
        }
    }

    return result;
};

function setsDifferenceModify(from, sets) {
    for (const value of from) {
        for (let i = 0; i < sets.length; i++) {
            if (sets[i].has(value)) {
                from.delete(value);
                break;
            }
        }
    }
}

Tests:

difference(from, [a, b, c]) - match
setsDifferenceModify(from, [match1, match2, match3]);
difference(from, [a, b, c]) - mismatch
setsDifferenceModify(from, [mismatch1, mismatch2, mismatch3]);
difference(from, [union(a, b, c)]) - match
setsDifferenceModify(from, [setsUnion(match1, match2, match3)]);
difference(from, [union(a, b, c)]) - mismatch
setsDifferenceModify(from, [setsUnion(mismatch1, mismatch2, mismatch3)]);

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
difference(from, [a, b, c]) - match
difference(from, [a, b, c]) - mismatch
difference(from, [union(a, b, c)]) - match
difference(from, [union(a, b, c)]) - mismatch

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:109.0) Gecko/20100101 Firefox/110.0

Browser/OS: Firefox 110 on Windows

View result in a separate tab

Test name	Executions per second
difference(from, [a, b, c]) - match	7646453.5 Ops/sec
difference(from, [a, b, c]) - mismatch	7690365.0 Ops/sec
difference(from, [union(a, b, c)]) - match	1038718.5 Ops/sec
difference(from, [union(a, b, c)]) - mismatch	1114121.5 Ops/sec

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

LLMs can make mistakes. Check important info.

Let's break down the benchmark and explain what is being tested.

**Overview**

The benchmark compares three different approaches to calculate the set difference between two sets in JavaScript:

1. Using the `delete` method on the original set (`setsDifferenceModify`)
2. Creating a new set using the `Set` constructor and iterating over the first set to remove matching elements (`difference` function)
3. Creating a union of all sets and then calculating the difference with the original set

**Options Compared**

The three options being compared are:

1. **Direct deletion**: Using the `delete` method on the original set to remove matching elements.
	* Pros: Efficient, as it only requires iterating over the first set once.
	* Cons: May not be suitable for large datasets, as it modifies the original set.
2. **Difference function**: Creating a new set using the `Set` constructor and iterating over the first set to remove matching elements.
	* Pros: Safe, as it doesn't modify the original set; can handle large datasets efficiently.
	* Cons: May be slower than direct deletion due to extra memory allocation and iteration.
3. **Union-based difference**: Creating a union of all sets and then calculating the difference with the original set.
	* Pros: Can handle large datasets efficiently, as it doesn't require iterating over the first set multiple times.
	* Cons: May be slower than direct deletion or difference function due to extra memory allocation and iteration.

**Library/Function Used**

The `difference` function is used in test cases 1-3. This function creates a new set by iterating over the first set and removing matching elements from the original set.

**Special JS Feature/Syntax**

None mentioned in this benchmark.

**Other Considerations**

When choosing an approach, consider the following factors:

* Dataset size: If the dataset is large, direct deletion or difference function may be more efficient. For very large datasets, union-based difference might be a better choice.
* Memory constraints: If memory allocation is a concern, difference function or direct deletion might be preferred over union-based difference.
* Performance requirements: If performance is critical, consider using a specialized library or optimizing the code for specific use cases.

**Alternatives**

Some alternative approaches to calculating set difference include:

* Using a `forEach` loop and adding elements to an empty set: This approach can be slower than direct deletion or difference function due to extra memory allocation.
* Using a `filter` method on the original set: This approach can be slower than direct deletion or difference function due to extra memory allocation.
* Using a library like Lodash's `difference` function: This approach can provide additional features and optimizations, but may introduce overhead.

Keep in mind that the choice of approach depends on specific use cases and requirements.

Related benchmarks:

Set difference vs set difference with union (version: 0)

Comparing performance of: difference(from, [a, b, c]) - match vs difference(from, [a, b, c]) - mismatch vs difference(from, [union(a, b, c)]) - match vs difference(from, [union(a, b, c)]) - mismatch

Created: one year ago by: Registered User

Jump to the latest result

difference(from, [a, b, c]) - match

difference(from, [a, b, c]) - mismatch

difference(from, [union(a, b, c)]) - match

difference(from, [union(a, b, c)]) - mismatch

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

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