Benchmark: Set has vs object key

Script Preparation code:

var obj = (new Array(1000)).fill(null).reduce((prev, newVal) => {prev[Math.random() + ''] = Math.random() + ''; return prev; }, { sausage: 'tst' });
var array = Object.keys(obj);
var set = new Set(array);

Tests:

Includes
array.includes('sausage')
Object[key]
obj['sausage']
Set.has
set.has('saudage')

Historical Performance Data aggregated from 197 community runs

Desktop Results:

Chrome 168 runs

Includes

29.6M/s

Set.has

29.5M/s

Object[key]

26.8M/s

Fastest: Includes (1.1x faster)

View exact numbers

✓ Includes: 29,588,168 ops/sec
• Set.has: 29,475,962 ops/sec
• Object[key]: 26,792,316 ops/sec

Firefox 14 runs

Set.has

1084.1M/s

Object[key]

950.2M/s

Includes

38.1M/s

Fastest: Set.has (28.4x faster)

View exact numbers

✓ Set.has: 1,084,099,200 ops/sec
• Object[key]: 950,166,400 ops/sec
• Includes: 38,133,000 ops/sec

Other 7 runs

Set.has

26.6M/s

Includes

26.0M/s

Object[key]

24.3M/s

View exact numbers

✓ Set.has: 26,580,010 ops/sec
• Includes: 26,030,394 ops/sec
• Object[key]: 24,307,112 ops/sec

Mobile Results:

Safari 8 runs

Object[key]

22.8M/s

Set.has

22.0M/s

Includes

21.9M/s

View exact numbers

✓ Object[key]: 22,797,896 ops/sec
• Set.has: 21,982,340 ops/sec
• Includes: 21,882,476 ops/sec

Results show median performance across all community submissions. Run this benchmark yourself to verify on your device.

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Includes
Object[key]
Set.has

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 7 months ago)

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:146.0) Gecko/20100101 Firefox/146.0

Browser/OS: Firefox 146 on Windows

View result in a separate tab

Set.has

755.2M/s

Object[key]

751.2M/s

Includes

24.3M/s

View exact numbers

Test name	Executions per second
✓ Set.has	755,223,808 Ops/sec
Object[key]	751,150,784 Ops/sec
Includes	24,313,642 Ops/sec

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

LLMs can make mistakes. Check important info.

I'll break down the provided benchmark and explain what's being tested.

**Benchmark Definition JSON**

The benchmark definition represents three different ways to check if an array contains a specific value:

1. `Set.has('sausage')`: This method checks if a Set object contains the string 'sausage'. A Set is an unordered collection of unique values.
2. `obj['sausage']`: This method accesses the property 'sausage' on the `obj` object, which is created by reducing an array with null values and adding random keys. This approach relies on object key lookups.
3. `array.includes('sausage')`: This method checks if the string 'sausage' exists in the `array`. The array contains a large number of unique random strings.

**Options Compared**

The benchmark compares three different approaches:

* **Set.has**: Using a Set data structure to check for membership. Sets are optimized for fast lookups and have an average time complexity of O(1).
* **Object[key]**: Accessing the property on the object using bracket notation (`obj['sausage']`). This approach relies on object key lookups, which can be slower than using a Set.
* **includes()**: Using the `array.includes()` method to check for membership in the array. This approach is generally faster than accessing individual elements of the array.

**Pros and Cons**

Here are some pros and cons of each approach:

* **Set.has**:
	+ Pros: Fast lookups, optimized for membership checks.
	+ Cons: May not work as expected with non-unique values or objects that have duplicate keys.
* **Object[key]**:
	+ Pros: Works well with objects that have unique keys.
	+ Cons: Can be slower than Set.has due to the overhead of property access and potential cache misses.
* **includes()**:
	+ Pros: Fast, efficient way to check for membership in arrays.
	+ Cons: May not work as expected if the array contains non-unique values or is very large.

**Library and Special JS Features**

The benchmark uses a JavaScript library called YaBrowser/24 (Yandex Browser), which provides a specific implementation of WebKit-based browsing. There are no special JS features mentioned in this benchmark, so I won't discuss any further.

**Other Alternatives**

If you're looking for alternative ways to check if an array contains a value, you could consider using:

* **Arrays.indexOf()**: This method returns the index of the first occurrence of the specified value. If the value is not found, it returns -1.
* **Arrays.includes() with spread operator**: You can use the spread operator (`[...array].includes()` to check if an array contains a value.

Keep in mind that these alternatives may have different performance characteristics and are not necessarily more efficient than the methods being compared in this benchmark.

Set has vs object key (version: 0)

performance comparison of ways to find if an array contains a value

Comparing performance of: `Includes vs Object[key] vs Set.has`

Created: 4 years ago by: Guest

Go to the latest result

Includes

Object[key]

Set.has

Historical Performance Data aggregated from 197 community runs

Desktop Results:

Chrome 168 runs

Firefox 14 runs

Other 7 runs

Mobile Results:

Safari 8 runs

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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

Set has vs object key (version: 0)

performance comparison of ways to find if an array contains a value

Comparing performance of: Includes vs Object[key] vs Set.has

Created: 4 years ago by: Guest

Go to the latest result

Includes

Object[key]

Set.has

Historical Performance Data aggregated from 197 community runs

Desktop Results:

Chrome 168 runs

Firefox 14 runs

Other 7 runs

Mobile Results:

Safari 8 runs

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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

Related benchmarks

Comparing performance of: `Includes vs Object[key] vs Set.has`