Benchmark: JS find vs indexOf vs Map

Script Preparation code:

var arr = [];
var ms = new Map();
var i = 0;

while (i <= 1E5) {
  arr[i] = i;
  ms.set(i, i);
  i++;
}

Tests:

Array.find
const item = arr.find(item => item == 1E5);
Array.indexOf
const index = arr.indexOf(1E5);
dsds
ms.has(1E5 - 1)

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Array.find
Array.indexOf
dsds

Fastest: N/A

Slowest: N/A

Latest run results:

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

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/125.0.0.0 Safari/537.36

Browser/OS: Chrome 125 on Mac OS X 10.15.7

View result in a separate tab

Test name	Executions per second
Array.find	2002.4 Ops/sec
Array.indexOf	87336.4 Ops/sec
dsds	24850028.0 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 benchmark and its test cases.

**Benchmark Overview**

The benchmark measures the performance of three different ways to find an element in an array or a Map: `find`, `indexOf`, and direct key lookup using a Map (`ms.has`).

**Script Preparation Code**

The script preparation code sets up two data structures:

1. An empty array `arr` with 100,000 elements, initialized with values from 0 to 99,999.
2. A new Map `ms` with the same keys as `arr`, but initialized with the same values.

**Individual Test Cases**

There are three test cases:

### Array.find

* Benchmark Definition: `const item = arr.find(item => item == 1E5);`
* Purpose: This test case measures the performance of the `find` method, which returns the first element in the array that satisfies the provided condition.
* Pros and Cons:
	+ Pros: The `find` method is a concise and expressive way to find an element in an array. It's also less prone to off-by-one errors compared to indexing-based approaches like `indexOf`.
	+ Cons: If the array is very large, iterating over all elements until finding the match can be slow.
* Notes: This test case uses a simple equality comparison (`item == 1E5`) to find the target element.

### Array.indexOf

* Benchmark Definition: `const index = arr.indexOf(1E5);`
* Purpose: This test case measures the performance of the `indexOf` method, which returns the first index at which the specified value can be found in the array.
* Pros and Cons:
	+ Pros: The `indexOf` method is a well-established and widely supported way to find an element in an array. It's also relatively fast compared to iterating over all elements.
	+ Cons: If the target value is not found, it throws an error.
* Notes: This test case uses direct indexing (`arr.indexOf(1E5)`), which may not be as efficient as using a `find` or `map` method for large arrays.

### Map lookup (dsds)

* Benchmark Definition: `ms.has(1E5 - 1)`
* Purpose: This test case measures the performance of direct key lookup using a Map.
* Pros and Cons:
	+ Pros: Direct key lookup is generally very fast, especially when used with optimized data structures like Maps.
	+ Cons: The comparison operator (`==`) may not be as efficient as other methods for finding matches in large arrays.
* Notes: This test case uses the `has` method of the Map to check if a key exists. Note that this assumes that the keys are hashed and stored in an optimized format.

**Browser and Device Information**

The benchmark result shows data from multiple browsers (Chrome 125 on Mac OS X 10.15.7) with different execution frequencies per second.

In summary, this benchmark measures the performance of three different methods for finding an element in a large array or Map: `find`, `indexOf`, and direct key lookup using a Map. The results provide insight into the relative efficiency of these approaches on modern browsers.

Related benchmarks:

JS find vs indexOf vs Map (version: 0)

JS find vs indexOf

Comparing performance of: Array.find vs Array.indexOf vs dsds

Created: 4 years ago by: Guest

Jump to the latest result

Array.find

Array.indexOf

dsds

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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