Benchmark: find vs findIndex vs for in (Array prototype methods)

Script Preparation code:

var arr = [];
var i = 0;

while (i <= 1E5) arr[i] = i++;

Tests:

Array.prototype.findIndex
const index = arr.findIndex(item => item == 1E5);
for if
let index = 0; for (const index in arr){ if (arr[index] == 1E5){ return index } }

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Array.prototype.findIndex
for if

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 3 years ago)

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/96.0.4664.93 Safari/537.36

Browser/OS: Chrome 96 on Mac OS X 10.15.7

View result in a separate tab

Test name	Executions per second
Array.prototype.findIndex	1391.7 Ops/sec
for if	135.3 Ops/sec

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

LLMs can make mistakes. Check important info.

Let's dive into the benchmark.

The provided JSON represents a JavaScript microbenchmark that measures the performance of three different approaches to find an element in an array:

1. **`Array.prototype.findIndex()`**: This method returns the index of the first element in the array that satisfies the provided condition (in this case, `item == 1E5`). If no such element is found, it returns `-1`.
2. **For-in loop with if statement**: This approach uses a traditional for-in loop to iterate over the array elements and checks each one using an if statement until the desired element is found.
3. **Traditional for loop**: This approach uses a traditional for loop to iterate over the array elements, incrementing the index variable `i` on each iteration.

**Options comparison:**

*   **FindIndex vs For-in Loop with If Statement**: Both approaches find the first occurrence of an element in the array that satisfies the condition. However:
    *   **FindIndex** is generally faster because it uses a more efficient algorithm that avoids the overhead of iterating over the array elements using a loop.
    *   **For-in Loop with If Statement** can be slower due to the additional overhead of the if statement and the loop itself.

*   **FindIndex vs Traditional For Loop**: This comparison might seem counterintuitive, but `FindIndex` is still likely to perform better. The traditional for loop has more overhead, including incrementing the index variable, checking each element, and potentially iterating over the entire array.

**Pros and Cons:**

*   **FindIndex**:
    *   Pros:
        *   Faster execution
        *   More concise code
    *   Cons:
        *   Less control over iteration (may not work for custom conditions)
        *   May have issues with edge cases or invalid input
*   **For-in Loop with If Statement**:
    *   Pros:
        *   More control over iteration and handling of edge cases
        *   Less dependence on the array's properties
    *   Cons:
        *   Less concise code
        *   Potentially slower execution
*   **Traditional For Loop**:
    *   Pros:
        *   High degree of control over iteration and loop logic
        *   Simple to implement for basic use cases
    *   Cons:
        *   More verbose code
        *   Generally slower execution due to additional overhead

**Library Usage:**

In this benchmark, the `Array.prototype.findIndex()` method is used, which is a built-in JavaScript function. This means that no external library or framework is required.

**Special JS Feature/Syntax:**

The benchmark uses a few special features:

*   **`1E5`**: This represents a scientific notation value (10^5). In JavaScript, this is equivalent to the number 100000.
*   **`const` and `let` keywords**: These are used for declaring variables with block scope. They are modern features introduced in ECMAScript 2015 (ES6) and later versions.

**Alternatives:**

If you're looking for alternative approaches to find an element in an array, some options include:

*   **Using a traditional for loop with the `indexOf()` method**: This is similar to the for-in loop approach but uses the built-in `indexOf()` method instead.
*   **Using a more advanced data structure like a Trie or binary search tree**: These data structures can provide faster lookup times, especially for large datasets.
*   **Using a library or framework that provides optimized array operations**: Some libraries, like Lodash or Ramda, offer optimized implementations of various array functions.

Related benchmarks:

find vs findIndex vs for in (Array prototype methods) (version: 0)

Measuring which is faster

Comparing performance of: Array.prototype.findIndex vs for if

Created: 3 years ago by: Guest

Jump to the latest result

Array.prototype.findIndex

for if

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

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