Benchmark: String in Array: Set vs IndexOf vs includes vs findIndex vs find

Script Preparation code:

var arr = [];
var i = 0;
while (i <= 10) arr[i] = ('' + i++);
var testSet = new Set(...arr);


var randomKeys = [];
i = 0;
while (i <= 50) {
 randomKeys.push(''+Math.round(Math.random(50000) + 5000));
  i++;
}

Tests:

indexOf
for (const key of randomKeys) {const index = arr.indexOf(key);}
includes
for (const key of randomKeys) {const index = arr.includes(key);}
find
for (const key of randomKeys) {const index = arr.find(item => item == key);}
findIndex
for (const key of randomKeys) {const index = arr.findIndex(item => item == key);}
set
for (const key of randomKeys) {const index = testSet.has(key);}

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
indexOf
includes
find
findIndex
set

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: one month ago)

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/134.0.0.0 Safari/537.36

Browser/OS: Chrome 134 on Mac OS X 10.15.7

View result in a separate tab

Test name	Executions per second
indexOf	1650944.2 Ops/sec
includes	1682715.1 Ops/sec
find	1238621.9 Ops/sec
findIndex	1227710.6 Ops/sec
set	14272984.0 Ops/sec

Autogenerated LLM Summary (model llama3.2:3b, generated 6 months ago):

LLMs can make mistakes. Check important info.

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

**Benchmark Overview**

The benchmark measures the performance of different methods for finding an element in an array: `indexOf`, `includes`, `findIndex`, `find`, and `set`. The test creates a large array with 51 elements (0-50) and a set containing all these elements. It then iterates over this set using various methods to find the presence of each element.

**Tested Options**

Here are the options being compared:

1. **indexOf**: Uses the `indexOf` method on the original array.
2. **includes**: Uses the `includes` method on the original array.
3. **findIndex**: Uses the `findIndex` method on the original array, which returns the index of the first occurrence of a specified value.
4. **find**: Uses the `find` method on the original array, which returns the first element in an array that satisfies a provided condition.
5. **set**: Uses the `has` method on the set to check if an element is present.

**Pros and Cons**

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

1. **indexOf**, **includes**, and **findIndex**: These methods are generally fast because they use an array index-based search algorithm. However, their performance can degrade if the array is very large or has duplicate elements.
2. **find**: This method uses a linear scan of the array to find the first occurrence of the specified value. It's slower than `indexOf` and `includes`, especially for larger arrays.
3. **set**: The `has` method on the set is particularly efficient because it only needs to check if the element is present in the set, without having to iterate over the entire array.

**Library**

In this benchmark, the `Set` class from JavaScript's built-in `Object` namespace is used. A set is a collection of unique values, which makes it ideal for fast membership testing (i.e., checking if an element is already present).

**Special JS Features/Syntax**

There are no specific JavaScript features or syntax used in this benchmark beyond what's required by the standard library (e.g., `Set`, `indexOf`, etc.).

**Alternatives**

If you wanted to write a similar benchmark, you could consider using other data structures, such as:

* A custom implementation of a set or hash table
* An array with duplicate elements
* A more complex data structure, like a trie or a suffix tree

However, keep in mind that these alternatives might not accurately represent the performance characteristics of your specific use case.

For a similar benchmark, you could also explore using different programming languages or frameworks to compare their performance on this specific microbenchmark.

Related benchmarks:

String in Array: Set vs IndexOf vs includes vs findIndex vs find (version: 0)

Comparing performance of: indexOf vs includes vs find vs findIndex vs set

Created: one year ago by: Guest

Jump to the latest result

indexOf

includes

find

findIndex

set

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 6 months ago):