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 llama3.1:latest, generated one year ago):

LLMs can make mistakes. Check important info.

Let's dive into the details of this benchmark.

**What is being tested?**

The benchmark compares two different approaches to look up an element in an array or an object by its key.

**Approach 1: Array lookup (Test Name: "Array")**

In this approach, a random index `lookupId` is generated between 0 and the length of the array. Then, a loop iterates over the array elements, checking if the first element of each pair (`array[i][0]`) matches the string `'id'+lookupId`. If it does, the second element of that pair (`array[i][1]`) is returned.

**Approach 2: Object lookup (Test Name: "Object")**

In this approach, a random key `lookupString` is generated as `'id'+lookupId`. Then, the `hasOwnProperty()` method is called on the object to check if it has a property with that name. If it does, the value of that property (`object[lookupString]`) is returned.

**What are the pros and cons of each approach?**

* **Array lookup:**
	+ Pros:
		- Can take advantage of array indexing for fast lookups.
		- Simple implementation.
	+ Cons:
		- Requires a loop to iterate over the entire array, which can be slow if the array is large.
		- Does not handle cases where the key is missing or invalid.
* **Object lookup:**
	+ Pros:
		- Can use object property access for fast lookups.
		- Handles cases where the key is missing or invalid (returns `undefined`).
	+ Cons:
		- Requires a more complex implementation with `hasOwnProperty()` and property access.
		- May be slower than array lookup due to the overhead of object lookups.

**Other considerations:**

* The benchmark uses a random index `lookupId` to simulate real-world usage patterns. This helps ensure that the results are not biased towards any particular approach.
* The test cases use a large number of iterations (5000) to stress-test both approaches and get accurate performance measurements.

**Library used: None**

There is no external library used in this benchmark. All code is written in plain JavaScript.

**Special JS feature or syntax: None**

No special JavaScript features or syntax are used in this benchmark.

**Alternatives:**

Other alternatives for looking up an element by its key include:

* Using a hash map (e.g., `Map` in modern JavaScript) to store the elements, which provides fast lookups.
* Implementing a custom indexing scheme, such as using a balanced binary search tree or a heap, to improve lookup performance.

However, these alternatives are not being compared in this specific benchmark.

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 llama3.1:latest, generated one year ago):