Benchmark: set.has vs string equals

Script Preparation code:

var keys = new Set([
	'a',
  'b',
  'c',
  'd',
  'e',
  'f'
])

var fn1 = (key) => keys.has(key)
var fn2 = (key) => key === 'a' || key === 'b' || key === 'c' || key === 'd' || key === 'e' || key === 'f'

Tests:

fn1
fn1('e') fn1('z')
fn2
fn2('e') fn2('z')

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
fn1
fn2

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 2 years ago)

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/121.0.0.0 Safari/537.36

Browser/OS: Chrome 121 on Windows

View result in a separate tab

Test name	Executions per second
fn1	7273925.5 Ops/sec
fn2	14079640.0 Ops/sec

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

LLMs can make mistakes. Check important info.

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

**Benchmark Definition**

The benchmark measures the performance difference between two JavaScript functions:

* `fn1`: uses the `Set` data structure to check if an element exists, using the `has()` method.
* `fn2`: uses a simple string equality check with multiple `||` conditions to check if a key matches one of the predefined values.

**Options Compared**

The benchmark compares two approaches:

1. **Using a Set**: This approach uses the `Set` data structure to store unique elements, allowing for efficient lookups using the `has()` method.
2. **String Equality Check**: This approach uses a simple string equality check with multiple `||` conditions to check if a key matches one of the predefined values.

**Pros and Cons**

* **Using a Set**:
	+ Pros: Efficient lookups, O(1) time complexity on average.
	+ Cons: Requires additional memory for storing the set, may not be suitable for large datasets.
* **String Equality Check**:
	+ Pros: Simple to implement, no additional memory required.
	+ Cons: Linear time complexity (O(n)), may lead to slower performance due to repeated string comparisons.

**Library and Purpose**

In this benchmark, the `Set` data structure is used. A Set in JavaScript is a collection of unique values, which allows for efficient lookups using the `has()` method.

**Special JS Feature or Syntax**

There are no special JS features or syntaxes being tested in this benchmark. The focus is on comparing two different approaches to achieve string equality checks.

**Other Alternatives**

Alternative approaches could include:

* Using regular expressions (regex) for string matching
* Using a library like Lodash's `isEqual()` function, which provides a more concise way of checking for equality between values
* Using a caching mechanism to store the results of previous lookups

Overall, this benchmark is designed to help developers understand the performance implications of using a Set vs. a simple string equality check in JavaScript.

Related benchmarks:

set.has vs string equals (version: 0)

Comparing performance of: fn1 vs fn2

Created: 2 years ago by: Guest

Jump to the latest result

fn1

fn2

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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