Benchmark: Array vs object - MeasureThat.net

Script Preparation code:

var n = 20;
var a = [];
var obj = {};
for (var i=0; i<a.length; i++) {
  a[i] = i;
  obj["obj" + i] = i;
}

Tests:

Array
r = Math.floor(Math.random()*n); for (var i=0; i<a.length; i++) { if (a[i] == r) break; }
Object
r = Math.floor(Math.random()*n); var i = obj["obj"+r];

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:

No previous run results

This benchmark does not have any results yet. Be the first one to run it!

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

LLMs can make mistakes. Check important info.

Let's dive into the world of JavaScript microbenchmarks on MeasureThat.net.

**Benchmark Overview**

The benchmark measures the performance difference between using arrays and objects in JavaScript for a simple search operation. The test creates an array and an object, populates them with numbers, and then searches for a randomly generated number within these data structures.

**Script Preparation Code**

The script preparation code initializes two variables: `n` (an integer), `a` (an empty array), and `obj` (an empty object). It then uses a `for` loop to populate the array and object with numbers, starting from 0 up to `n-1`. The goal is to create a large dataset that will be used for benchmarking.

**HTML Preparation Code**

There is no HTML preparation code provided in this example. This might mean that the test focuses solely on JavaScript performance, without considering DOM manipulation or rendering.

**Individual Test Cases**

There are two individual test cases:

1. **Array**: The first test case uses a traditional array (`a`) and searches for a randomly generated number using `for` loop.
```javascript
r = Math.floor(Math.random()*n);
for (var i=0; i<a.length; i++) {
  if (a[i] == r) break;
}
```
This approach is straightforward and easy to understand.

2. **Object**: The second test case uses an object (`obj`) with dynamic keys (`"obj" + i`), which is similar to the array, but with an object-oriented twist.
```javascript
r = Math.floor(Math.random()*n);
var i = obj["obj"+r];
```
This approach leverages JavaScript's ability to create objects dynamically.

**Pros and Cons**

Here are some pros and cons of each approach:

* **Array**: Pros:
	+ Easy to understand and implement.
	+ Fast iteration using `for` loop.
	+ No additional memory allocation required for dynamic key storage.
*   Cons:
    *   May be slower due to the need to access elements by index (0-based).
*   Object: Pros:
    + Can take advantage of JavaScript's object-oriented features and dynamic property lookup.
    + May offer better cache locality, as objects are stored in contiguous memory.
    + Faster iteration using object properties.
*   Cons:
    + More complex implementation due to the need for dynamic key storage.
    + May incur additional memory overhead.

**Library Usage**

In this benchmark, no external libraries are used. The script and object creation rely solely on built-in JavaScript features.

**Special JS Feature/ Syntax**

The test case uses a special feature of JavaScript: **dynamic property lookup**. In the `Object` test case, the key `"obj" + i` is dynamically generated using string concatenation. This allows for flexible and dynamic storage of data in objects.

**Alternatives**

Other alternatives to consider when benchmarking array vs object performance include:

1. Using a different data structure, such as a linked list or a set.
2. Adding additional complexity to the search operation (e.g., sorting, filtering).
3. Using a Just-In-Time (JIT) compiler or optimizing the JavaScript code for specific use cases.

By considering these alternatives and using MeasureThat.net's benchmarking tool, developers can gain valuable insights into the performance characteristics of different data structures and algorithms in JavaScript.

Related benchmarks:

Array vs object (version: 0)

Comparing performance of: Array vs Object

Created: 8 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 llama3.2:3b, generated one year ago):