Benchmark: Map vs Object getter

Script Preparation code:

var map = new Map();
var obj = {};

map.set('a', 5);
obj['a'] = 5;

var i = 0, count = 1000, a;

Tests:

Map lookup
obj.a;
Obj lookup
map.get("a");

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

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

LLMs can make mistakes. Check important info.

Let's dive into the world of JavaScript microbenchmarks.

**What is tested?**

The benchmark measures the performance difference between accessing an element using `obj.a` (object getter) and `map.get("a")` (map lookup). The test cases are designed to create a map and an object, set an element on both data structures, and then look up that element. The goal is to compare the speed of these two approaches.

**Options compared**

The benchmark compares two options:

1. **Object Getter (`obj.a`)**: This approach uses the dot notation (`.a`) to access the element in the object.
2. **Map Lookup (`map.get("a")`)**: This approach uses the `get()` method of the Map data structure to retrieve the value associated with a given key.

**Pros and Cons**

**Object Getter (`obj.a`)**

Pros:

* Simple and easy to understand
* Works well for small to medium-sized datasets

Cons:

* May be slower than map lookup due to object property access overhead (e.g., resolving `a` in the dot notation)
* Can lead to slower performance if the object grows large, as it requires traversing a nested structure

**Map Lookup (`map.get("a")`)**

Pros:

* Often faster than object getter for large datasets, as map lookups are typically optimized and more efficient
* Allows for easy addition or removal of elements without modifying the underlying data structure

Cons:

* May require additional memory to store the key-value pairs
* Can be slower for small datasets due to the overhead of creating and searching the map

**Library: `Map`**

The Map data structure is a built-in JavaScript object that allows you to store mappings of keys to values. In this benchmark, the Map is used to demonstrate its lookup efficiency. The `get()` method is used to retrieve the value associated with a given key.

**Special JS feature/syntax**

There isn't any specific special JavaScript feature or syntax mentioned in this benchmark. However, if you're interested in exploring other optimizations, you might want to look into:

* Using `const` and `let` declarations instead of `var` for better scoping
* Utilizing the `for...of` loop or `Array.prototype.forEach()` for array operations
* Leveraging WebAssembly (WASM) for low-level performance optimization

**Other alternatives**

For this specific benchmark, other alternatives to compare would be:

* Using a different data structure, such as an object with nested properties or an array-based approach
* Implementing your own custom lookup function using recursion or iteration
* Comparing the performance of different JavaScript engines (e.g., V8, SpiderMonkey)

Latest run results:

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

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/105.0.0.0 Safari/537.36

Browser/OS: Chrome 105 on Mac OS X 10.15.7

View result in a separate tab

Test name	Executions per second
Map lookup	27284672.0 Ops/sec
Obj lookup	27494746.0 Ops/sec

Related benchmarks:

Map vs Object getter (version: 0)

Lookup of map vs object getter

Comparing performance of: Map lookup vs Obj lookup

Created: 4 years ago by: Guest

Jump to the latest result

Map lookup

Obj lookup

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

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