Benchmark: Set has vs object key vs map has

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);
var map = new Map(Object.entries(obj));

Tests:

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

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

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

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 26 days ago):

LLMs can make mistakes. Check important info.

Let's break down the provided benchmark and its options.

**Benchmark Definition**
The main goal of this benchmark is to compare the performance of three methods for checking if an array contains a specific value:

1. `array.includes('sausage')`
2. `obj['sausage']` (using object key lookup)
3. `set.has('sausage')` (using Set has method)
4. `map.has('sausage')` (using Map has method)

**Options Comparison**

The options being compared are:

* `array.includes()`: checks if a value exists in an array by iterating over the elements and checking for equality.
* `obj['sausage']`: uses object key lookup to access a property of an object. In this case, the property is accessed using a random string as the key, making it unlikely to be present in most objects.
* `set.has()`: checks if a value exists in a Set data structure by iterating over its elements and checking for equality.
* `map.has()`: checks if a value exists in a Map data structure by accessing its entries and checking for existence.

**Pros and Cons of Each Approach**

1. `array.includes()`:
	* Pros: widely supported, fast for small arrays.
	* Cons: slow for large arrays due to iteration over all elements.
2. `obj['sausage']`:
	* Pros: fast for objects with many properties, as it directly accesses a property using its key.
	* Cons: slow for objects without the desired property, and this benchmark uses a random property name, making it less likely to be present in most objects.
3. `set.has()`:
	* Pros: fast for large sets of unique values, as it uses a data structure optimized for lookups.
	* Cons: requires creating a Set instance, which can be slow if not necessary.
4. `map.has()`:
	* Pros: fast for maps with many entries, as it directly accesses an entry using its key.
	* Cons: requires creating a Map instance, which can be slow if not necessary.

**Library and Purpose**
In the provided benchmark script, the following libraries are used:

* `Array.prototype.includes()`: part of the ECMAScript standard, providing a way to check for membership in an array.
* `Object.keys()`, `Set`, and `Map`: built-in JavaScript objects that provide functionality for working with data structures.

**Special JS Feature or Syntax**
The benchmark uses a feature called "reducer" from the `Array.prototype` method. The reducer function is used to create an array of random strings, which is then used to generate a random object (`obj`). This allows the benchmark to test the performance of each option in a controlled environment.

**Other Alternatives**

Alternative methods for checking if an array contains a value could include:

* `array.indexOf()` or `array.lastIndexOf()`: these methods search for the specified value from both ends of the array.
* `array.includes()` with a custom iterator: this approach would allow testing more complex iteration patterns, but is not widely supported and may be slower than `includes()`.
* Using a more specialized data structure, such as a Trie or a prefix tree, to store the values being searched for.

Latest run results:

Run details: (Test run date: 5 months ago)

User agent: Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/117.0.0.0 Safari/537.36

Browser/OS: Chrome 117 on Linux

View result in a separate tab

Test name	Executions per second
Includes	19751860.0 Ops/sec
Object[key]	17276298.0 Ops/sec
Set.has	19009556.0 Ops/sec
Map.has	18632666.0 Ops/sec

Related benchmarks:

Set has vs object key vs map has (version: 0)

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

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

Created: 5 months ago by: Registered User

Jump to the latest result

Includes

Object[key]

Set.has

Map.has

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 26 days ago):