Benchmark: Array.indexOf vs Object lookup small collection

Script Preparation code:

var o = {'ff1234567890121':0, 'ff1234567890122':1, 'ff1234567890123':2, 'ff1234567890124':3};
var a = ['ff1234567890121', 'ff1234567890122', 'ff1234567890123', 'ff1234567890124'];
var t = 'ff1234567890124';

Tests:

Array indexOf
var i = a.indexOf(t);
Object lookup
var i = o[t];

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Array indexOf
Object lookup

Fastest: N/A

Slowest: N/A

Latest run results:

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

User agent: Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/131.0.0.0 Safari/537.36

Browser/OS: Chrome 131 on Linux

View result in a separate tab

Test name	Executions per second
Array indexOf	33119330.0 Ops/sec
Object lookup	68928408.0 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 definition and test cases to understand what is being tested.

**Benchmark Definition**

The benchmark defines two test cases: `Array.indexOf` and `Object lookup`. Both tests are designed to measure the performance of searching for a specific value in an array or object using different methods.

**Script Preparation Code**

The script preparation code sets up two variables:

* `o`: An object with a small collection of properties, where each property has a corresponding integer value.
* `a`: An array containing the same keys as the object `o`, but in a different order.
* `t`: A string key that is used to search for in both `a` and `o`.

**Html Preparation Code**

There is no HTML preparation code provided, which means that this benchmark is focused on JavaScript performance and does not involve any external dependencies or resources.

**Individual Test Cases**

The two test cases are:

1. **Array.indexOf**: This test case measures the performance of using the `indexOf` method to search for the value `t` in the array `a`.
2. **Object lookup**: This test case measures the performance of directly accessing the value associated with the key `t` in the object `o`.

**Library and Purpose**

In both test cases, a library or function is used to perform the search:

* In `Array.indexOf`, the built-in JavaScript method `indexOf` is used.
* In `Object lookup`, the built-in JavaScript property access syntax (e.g., `o[t]`) is used.

Both of these approaches are straightforward and efficient ways to search for a value in an array or object.

**Pros and Cons**

Here are some pros and cons of each approach:

* **Array.indexOf**:
	+ Pros: Simple and widely supported, can be used with any type of array.
	+ Cons: May require additional iterations if the element is not found, can be slower for very large arrays.
* **Object lookup**:
	+ Pros: Can be faster for direct property access, does not require iterating over elements.
	+ Cons: Requires knowledge of object keys and may be less readable in complex scenarios.

**Other Considerations**

When measuring performance between these two approaches, it's essential to consider the following:

* The size of the array or object being searched.
* The type of data being stored (e.g., strings, numbers, objects).
* The specific use case and requirements of the application.

**Alternatives**

If you want to explore alternative approaches, here are a few options:

* Using `for` loops or other iteration methods to search for an element in an array.
* Using `Object.keys()` or `Object.values()` to iterate over object properties.
* Using specialized libraries like Lodash or Ramda for functional programming approaches.

Keep in mind that these alternatives may have different performance characteristics and trade-offs, so it's essential to test and evaluate them based on your specific use case.

Related benchmarks:

Array.indexOf vs Object lookup small collection (version: 0)

Comparing performance of: Array indexOf vs Object lookup

Created: 7 years ago by: Guest

Jump to the latest result

Array indexOf

Object lookup

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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