Benchmark: Array loop vs hasownproperty

Script Preparation code:

var object = {};
var array = [];

function randomIntFromInterval(min, max) { // min and max included 
  return Math.floor(Math.random() * (max - min + 1) + min);
}

for(let i = 0; i < 5000; i++){
	object['id'+i] = true;
  array.push(['id'+i, true]);
}

Tests:

Array
let lookupId = randomIntFromInterval(0, 5000); for(let i = 0; i < array.length; i++){ if(array[i][0] == 'id'+lookupId){ return array[i][1]; } }
Object
let lookupId = randomIntFromInterval(0, 5000); let lookupString = 'id'+lookupId; if(object.hasOwnProperty(lookupString)){ return object[lookupString]; }

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Array
Object

Fastest: N/A

Slowest: N/A

Latest run results:

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

LLMs can make mistakes. Check important info.

This benchmark compares two ways of finding a value in a dataset: using an array and using an object with `hasOwnProperty()`.

**Let's break down the setup:**

* **Data Preparation:** The script creates both an array (`array`) and an object (`object`). Both contain 5000 key-value pairs where the keys are strings like "id0", "id1", ..., "id4999" and the values are all set to `true`.

**The Tests:**

* **Array Approach ("Array" Test):** The benchmark generates a random index (`lookupId`) within the 5000 range. Then, it iterates through each element in the `array` using a `for` loop. For every element, it checks if the first property (which is a string like "id" followed by the index) matches the `lookupId`. If there's a match, it returns the second property (`true`).

* **Object Approach ("Object" Test):** This test also generates a random index (`lookupId`) and constructs a key based on that index. It then uses the `hasOwnProperty()` method to check if the object has a property with that specific key. If it does, it returns the value associated with that key.

**Pros and Cons:**

* **Array Approach:**
    * **Pros:**  Can be faster for large arrays with sequential access patterns because you're directly accessing elements by their index.
    * **Cons:**  If your data is not sequential or if keys are not predictable, searching through an array can be slow.

* **Object Approach:**
    * **Pros:** More efficient for looking up values based on specific keys, even if the order of the data isn't important. JavaScript's object property lookup mechanisms are generally optimized.
    * **Cons:** Can be slower than arrays when you need to iterate over all elements in a deterministic order.

**Other Considerations:**

* **Data Size:** The performance difference between these two approaches becomes more significant as your dataset grows.

* **Frequency of Lookups:** If you're performing frequent lookups based on specific keys, the object approach is likely more suitable.
* **Additional Libraries/Features:** This benchmark doesn't use any special libraries or JavaScript features.

**Alternatives:**

* **Maps (JavaScript):** Maps are a specialized data structure in JavaScript that provide fast key-value lookups similar to objects but with some performance advantages, especially for large datasets.

Let me know if you have any more questions!

Related benchmarks:

Array loop vs hasownproperty (version: 0)

Comparing performance of: Array vs Object

Created: 6 years ago by: Guest

Jump to the latest result

Array

Object

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

No previous run results

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