Benchmark: Map vs Object.create(null)

Script Preparation code:

var map = new Map();
var obj = Object.create(null);

for (let i = 0; i < 20; ++i) {
  map.set(i, i)
  obj[i] = i
}

var i = 0, count = 1000, a;

Tests:

Map lookup
for (i = 0; i < count; i++) { a = map.get(i % 20); }
Obj lookup
for (i = 0; i < count; i++) { a = obj[i % 20]; }

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Map lookup
Obj lookup

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 24 days ago)

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/146.0.0.0 Safari/537.36 Edg/146.0.0.0

Browser/OS: Chrome 146 on Windows

View result in a separate tab

Test name	Executions per second
Map lookup	6201.9 Ops/sec
Obj lookup	6751.9 Ops/sec

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

LLMs can make mistakes. Check important info.

Let's break down the provided benchmark and explain what's being tested.

**Benchmark Overview**

The benchmark is comparing two approaches for storing and retrieving data: `Map` and `Object.create(null)`. A `Map` is a built-in JavaScript object that stores key-value pairs, while `Object.create(null)` creates an object with no prototype chain.

**Options Compared**

The two options being compared are:

1. **`Map`**: Storing data in a `Map` object using the `set()` method to add key-value pairs and the `get()` method to retrieve values.
2. **`Object.create(null)`**: Creating an object with no prototype chain using `Object.create(null)`, then storing data in it using bracket notation (`obj[key] = value`) and property access (`obj[key]`). The data is also added using `obj[key] = value`.

**Pros and Cons**

* **`Map`**:
	+ Pros: Efficient lookup, insertion, and deletion of key-value pairs. Provides a more modern and concise way to store data.
	+ Cons: May have higher overhead due to its internal implementation, which can affect performance in some cases.
* **`Object.create(null)`**:
	+ Pros: Can provide better control over the object's prototype chain and may be more suitable for certain use cases. It also allows for more explicit management of data storage.
	+ Cons: Requires more manual effort to manage data, as it doesn't provide a built-in way to add or retrieve key-value pairs like `Map` does.

**Library and Purpose**

In the provided benchmark definition JSON, the `Map` object is used. A `Map` is a built-in JavaScript object that provides an efficient way to store and retrieve key-value pairs.

**Special JS Feature/Syntax**

There are no special JavaScript features or syntax mentioned in this benchmark. It focuses on comparing two basic approaches for storing data.

**Other Considerations**

When choosing between these two options, consider the following:

* Use a `Map` when you need efficient lookup, insertion, and deletion of key-value pairs.
* Use `Object.create(null)` when you require more control over the object's prototype chain or need to manually manage data storage.

**Alternatives**

Other alternatives for storing data in JavaScript include:

1. **Arrays**: Suitable for storing sequential data, but may not provide efficient lookup or insertion operations.
2. **IndexedDB**: A client-side storage mechanism that provides a more robust and scalable way to store structured data.
3. **Object literal notation**: Used to create objects with named properties (e.g., `var obj = { foo: 'bar' };`). While convenient, this approach can lead to slower performance compared to using a `Map` or `Object.create(null)`.

Keep in mind that the best choice for storing data ultimately depends on the specific requirements and constraints of your project.

Related benchmarks:

Map vs Object.create(null) (version: 0)

Lookup of map vs object

Comparing performance of: Map lookup vs Obj lookup

Created: 3 years ago by: Guest

Jump to the latest result

Map lookup

Obj lookup

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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