Benchmark: Map vs Object - MeasureThat.net

Script Preparation code:

var map = new Map();
map.set("att", "value");

var object = {
  att: "value"
}

Tests:

Map
map.get("att")
Object
object.att

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Map
Object

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: one year ago)

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:138.0) Gecko/20100101 Firefox/138.0

Browser/OS: Firefox 138 on Windows

View result in a separate tab

Test name	Executions per second
Map	954740224.0 Ops/sec
Object	987751104.0 Ops/sec

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

LLMs can make mistakes. Check important info.

Let's break down what's being tested in this JavaScript microbenchmark.

**Benchmark Definition**

The benchmark is comparing the performance of accessing an attribute on an object versus using a `Map` data structure to store key-value pairs.

**Options Compared**

Two options are being compared:

1. **Accessing an attribute directly on an object**: The code `object.att` is executed, which accesses the `att` property of the `object` variable.
2. **Using a `Map` to store and retrieve values by key**: The code `map.get("att")` is executed, which retrieves the value associated with the key `"att"` from the `map` object.

**Pros and Cons**

* **Accessing an attribute directly on an object**:
	+ Pros: Simple and intuitive way to access attributes.
	+ Cons: May involve additional overhead for complex objects, as the browser needs to resolve the property path (e.g., `object.att`). Additionally, if the object is large or has many nested properties, this approach may be slower due to increased parsing and resolution time.
* **Using a `Map`**:
	+ Pros: Faster lookups, especially for large datasets, since maps use hash tables for storage. Maps also provide more flexibility in terms of key types (e.g., strings, numbers, objects).
	+ Cons: May require additional setup and initialization time to create the map, and the lookup process may be slightly slower due to the need to hash and search the map.

**Library and Its Purpose**

In this benchmark, `Map` is a built-in JavaScript object that stores key-value pairs. The `Map` data structure provides an efficient way to store and retrieve values by key, making it useful for scenarios where fast lookups are critical.

**Special JS Feature or Syntax**

None mentioned in the provided code snippet.

**Other Considerations**

When deciding between accessing attributes directly on an object versus using a `Map`, consider the following factors:

* **Data structure complexity**: If your data is relatively simple and has few keys, direct attribute access might be sufficient. For larger datasets or more complex structures, a `Map` may provide better performance.
* **Frequent lookups**: If you need to frequently retrieve values by key, using a `Map` can be beneficial.
* **Memory usage**: `Maps` generally consume more memory than objects due to the additional storage required for each key-value pair.

**Alternatives**

If you're considering alternative approaches, here are a few options:

* **Arrays**: If your data is sequential and you need to access elements by index, arrays might be a good choice.
* **Sparse Arrays or Objects**: If you have many missing keys in your object, using a sparse array or object can reduce memory usage and improve performance for lookups.
* **Custom Data Structures**: Depending on your specific use case, creating a custom data structure tailored to your needs might provide better performance.

These alternatives should be considered only when the built-in `Map` doesn't meet your requirements.

Related benchmarks:

Map vs Object (version: 1)

Comparing performance of: Map vs Object

Created: 9 years ago by: Registered User

Jump to the latest result

Map

Object

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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