Benchmark: object vs array performance123232

Script Preparation code:

var obj = new Object();
var keys = new Array(100).fill(0).map((x, i) => {
  return i + 1;
});
keys.forEach((x) => {
  obj["prop" + x] = {
    value: x
  };
});

var array = [];

let i = 0;
for (i; i < 100; i++) {
  array[i] = {
    props: "prop" + i,
    value: i
  };
}

Tests:

Object
if (obj.hasOwnProperty('prop98')) { console.log(obj['prop98']) }
Array
array.forEach((value) => { if (value.props === "prop98") { console.log(value.value); } });

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Object
Array

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 2 years ago)

User agent: Mozilla/5.0 (iPhone; CPU iPhone OS 15_4 like Mac OS X) AppleWebKit/605.1.15 (KHTML, like Gecko) Version/15.4 Mobile/15E148 DuckDuckGo/7 Safari/605.1.15

Browser/OS: Mobile Safari 15 on iOS 15.4

View result in a separate tab

Test name	Executions per second
Object	662871.9 Ops/sec
Array	186478.5 Ops/sec

Autogenerated LLM Summary (model llama3.2:3b, generated 6 months ago):

LLMs can make mistakes. Check important info.

I'll break down the provided benchmark and explain what's being tested, compared, and its implications.

**Benchmark Overview**

The provided benchmark consists of two test cases: `Object` and `Array`. The goal is to compare the performance of accessing properties in JavaScript objects versus arrays.

**Benchmark Definition JSON**

The `Script Preparation Code` section creates:

1. An object (`obj`) with 100 properties, each containing a value.
2. An array (`keys`) with 100 elements, where each element is an index (from 1 to 100).

**Test Cases**

There are two test cases:

### Object Test Case

The `Benchmark Definition` code checks if the property `prop98` exists in the object `obj`. If it does, it logs the value of that property.

In other words, this test case measures how fast JavaScript can access a specific property in an object.

### Array Test Case

The `Benchmark Definition` code uses `forEach` to iterate over the array (`keys`) and checks if any element's `props` property is equal to `"prop98"`. If it finds such an element, it logs the value of that element's `value` property.

This test case measures how fast JavaScript can access a specific property in an array using a loop.

**Comparison**

The two test cases are designed to compare the performance of accessing properties in objects versus arrays. The idea is to see which approach (object or array) is faster for this specific use case.

**Pros and Cons**

**Object Approach:**

Pros:

* Objects are often used when you need to store data with a fixed set of properties.
* Accessing an object's property can be faster if the property exists, as it involves a simple lookup.

Cons:

* Objects have a higher memory overhead compared to arrays for storing a large number of values.
* Property access in objects can be slower if the object is very large or has many unnecessary properties.

**Array Approach:**

Pros:

* Arrays are optimized for random access and can be faster when you need to access a specific element by its index.
* Arrays use less memory than objects when storing a large number of values.

Cons:

* Array iteration using `forEach` can be slower than direct property access in objects, especially if the array is very large.
* The loop can introduce unnecessary overhead due to function call and iteration.

**Library: None**

There are no libraries used in this benchmark. However, the use of `forEach` in the array test case suggests that JavaScript's built-in `Array.prototype.forEach` method is being utilized.

**Special JS Feature/Syntax: None**

There are no special JavaScript features or syntaxes used in this benchmark.

**Alternative Approaches**

Other approaches to compare these two:

* **Direct Property Access:** Instead of using `obj.hasOwnProperty()` and array indexing, you could directly access the property using bracket notation (`obj['prop98']`).
* **Iterating over Object Properties:** You could use a `for...in` loop or `Object.keys()` method to iterate over object properties instead of using `hasOwnProperty()`.
* **Using a Custom Data Structure:** You could create a custom data structure that combines the benefits of objects and arrays, such as an array-like object with object properties.

These alternative approaches would likely have different performance characteristics and might be more suitable depending on the specific use case.

Related benchmarks:

object vs array performance123232 (version: 0)

Comparing performance of: Object vs Array

Created: 2 years 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 llama3.2:3b, generated 6 months ago):