Benchmark: benchmark for time Array access vs Object access

Script Preparation code:

var items = Array.from(Array(100), (_, x) => ({
    key: x,
    value: x * 10
}));

var objContainer = {};
var arrContainer = [];

for (let i = 0; i <= 100; ++i) {
    const item = items[i];
    objContainer[i] = item;
    arrContainer.push(item);
}

Tests:

Array
items.forEach((_, idx) => objContainer[idx])
Object
items.forEach((_, idx) => objContainer[idx])

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:

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

User agent: Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/121.0.0.0 Safari/537.36

Browser/OS: Chrome 121 on Linux

View result in a separate tab

Test name	Executions per second
Array	175687.6 Ops/sec
Object	168875.3 Ops/sec

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!

The provided JSON represents a benchmark test case created on MeasureThat.net. The goal of this benchmark is to compare the performance of accessing an array element versus accessing an object property.

**Options being compared:**

1. Array access (`items.forEach((_, idx) => objContainer[idx])`)
2. Object access (`objContainer[idx]`)

**Pros and Cons:**

* **Array access:** This approach uses the `forEach` method to iterate over the array, which can be a convenient way to access elements by index. However, it may incur overhead due to the iterator's behavior.
	+ Pros: Can be efficient for large arrays with incremental indexing.
	+ Cons: May introduce unnecessary overhead due to the `forEach` method's internal workings.
* **Object access:** This approach directly accesses the object property using the `objContainer[idx]` syntax, which can be a straightforward way to retrieve values by index.
	+ Pros: Typically faster and more efficient than array access methods.
	+ Cons: May require additional memory allocations or checks for valid indices.

In general, accessing an object property is likely to be faster than iterating over an array using `forEach`. This is because objects are typically implemented as hash tables, which allow for fast lookups by index. Arrays, on the other hand, use a more complex indexing system that may incur additional overhead.

**Library usage:**

None of the benchmark test cases explicitly use any external libraries. However, MeasureThat.net might be using some internal library or framework to facilitate benchmarking and data analysis.

**Special JavaScript features or syntax:**

The benchmark uses ES6+ syntax, including:

* Arrow functions (`( _, idx ) => { ... }`)
* Template literals (`var items = Array.from(Array(100), (_, x) => ({ key: x, value: x * 10 }));`)
* Destructuring assignment (`const item = items[i];`)

These features are not specific to the benchmark's performance but rather reflect the author's preference for concise and modern JavaScript code.

**Other alternatives:**

If you wanted to create a similar benchmark, you could consider exploring other approaches, such as:

* Using `Array.prototype.map()` or `Array.prototype.reduce()` to access elements by index.
* Implementing your own indexing system using a data structure like an object or a hash table.
* Using a different JavaScript engine or runtime environment (e.g., Node.js vs. browser-based engines) to compare performance.

Keep in mind that each alternative approach would require significant modifications to the benchmark code and might introduce additional overhead or complexity.

Related benchmarks:

benchmark for time Array access vs Object access (version: 0)

Comparing performance of: Array vs Object

Created: 2 years ago by: Guest

Jump to the latest result

Array

Object

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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