Benchmark: access object vs array

Tests:

object
let obj = {}; let n = 10000; while (n--) { obj['id-'+i]=n; } const res = obj['id-1000'];
array
let arr = []; let n = 10000; while (n--) { arr.push({name:'id-'+i,value:n}); } const res = arr.find(x=>x.name=='id-1000');

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
object
array

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model gemma2:9b, generated one month ago):

LLMs can make mistakes. Check important info.

This benchmark tests the performance of accessing data in objects versus arrays in JavaScript.

Let's break down how it works:

**Object Approach:**

* **Code:**  The code creates an empty object (`obj`) and then iterates 10,000 times, adding a property to the object with the key `id-` followed by a number (e.g., `id-1`). Finally, it accesses the property `id-1000`.
* **Concept:** In JavaScript, objects use key-value pairs for data storage. Accessing an element in an object requires a lookup based on its unique key.

**Array Approach:**

* **Code:** The code creates an empty array (`arr`) and iterates 10,000 times, pushing an object with the properties `name` (e.g., `id-1`) and `value` into the array. Finally, it uses the `find()` method to locate the object where the `name` property is equal to `id-1000`.
* **Concept:** Arrays are a linear collection of data, so accessing elements by index (position) is very efficient.

**Pros and Cons:**

| Approach | Pros                                   | Cons                                    |
|----------|----------------------------------------|-----------------------------------------|
| Object   | Data can be accessed using any key   | Accessing specific data can be slower due to the lookup process |
| Array    | Fast access by index                 | Requires knowing the index of the desired element |

**Other Considerations:**

* **Data Structure:** The choice between objects and arrays depends heavily on the nature of your data. Objects are suitable for structured data with meaningful keys, while arrays excel when you need to store a sequence of items.
* **Operations:** Arrays offer built-in methods like `push()`, `pop()`, `slice()`, which make manipulating sequences efficient. Objects often require more explicit coding for similar operations.

**Alternatives:**

Beyond objects and arrays, JavaScript provides:

* **Maps:**  A key-value data structure similar to objects but with better performance for large datasets.
* **Sets:**  Collections of unique values that efficiently check for membership.

Let me know if you have any more questions!

Latest run results:

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

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/117.0.0.0 Safari/537.36

Browser/OS: Chrome 117 on Windows

View result in a separate tab

Test name	Executions per second
object	2189.0 Ops/sec
array	4981.1 Ops/sec

Related benchmarks:

access object vs array (version: 0)

Comparing performance of: object vs array

Created: one year ago by: Guest

Jump to the latest result

object

array

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model gemma2:9b, generated one month ago):