Benchmark: Map vs Object v2

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
for (i = 0; i < count; i++) { a = map.get('a'); if(a !== 5){ throw new Error(); } }
Obj lookup
for (i = 0; i < count; i++) { a = obj['a']; if(a !== 5){ throw new Error(); } }

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:

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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, the options compared, their pros and cons, and other considerations.

**Benchmark Overview**

The benchmark is designed to compare the performance of two data structures in JavaScript: Maps and objects (specifically, object notation with bracket notation).

**Script Preparation Code**

The script preparation code creates an empty Map (`var map = new Map();`) and an empty object (`var obj = {};`). It then sets a single value on both the Map and the object using the `set()` method for the Map and the assignment operator (`obj['a'] = 5;`) for the object.

**Benchmark Test Cases**

There are two test cases:

1. **Map lookup**: This test case uses the `get()` method to retrieve the value associated with a given key from the Map.
2. **Object lookup**: This test case uses the bracket notation (`obj['a']`) to access the value associated with a given key in the object.

**Library and Purpose**

The `Map` class is part of the JavaScript API, which provides an implementation for associative arrays (also known as hash tables or dictionaries). The purpose of this class is to store key-value pairs in a data structure that allows efficient lookup, insertion, and deletion of values based on their keys.

**Special JS Feature/ Syntax**

There are no special features or syntaxes being used in this benchmark. However, it's worth noting that the `Map` class provides additional methods beyond just `get()`, such as `has()`, `set()`, `delete()`, and `size()`.

**Options Compared**

The two options being compared are:

1. **Map lookup**: This uses the `get()` method to retrieve values from a Map.
2. **Object lookup**: This uses bracket notation (`obj['a']`) to access values in an object.

**Pros and Cons**

Here's a brief summary of the pros and cons of each approach:

* **Map lookup (get())**:
	+ Pros: Efficient for large datasets, as Maps can handle arbitrary key types and sizes.
	+ Cons: May incur overhead due to the `get()` method's implementation, which may involve traversing the Map's internal hash table.
* **Object lookup (bracket notation)**:
	+ Pros: Lightweight, as bracket notation only accesses a specific property on an object without creating any additional overhead.
	+ Cons: May be slower for large datasets, as it requires iterating over the object's properties to find the desired key.

**Other Considerations**

When choosing between these two approaches, consider the following factors:

* **Data size and structure**: If you're working with a small to medium-sized dataset, bracket notation might be sufficient. For larger datasets or more complex data structures, Maps are likely to provide better performance.
* **Key type and complexity**: If your keys are simple strings or numbers, Maps will perform better. However, if your keys are more complex (e.g., objects), Maps can handle them efficiently using their `Map` class.

**Alternatives**

Other alternatives for data structures in JavaScript include:

* **Array**: Arrays provide efficient indexing and iteration, but they're limited to numerical indices.
* **Set**: Sets provide an efficient way to store unique values, with operations like `add()`, `has()`, and `delete()`.
* **WeakMap**: WeakMaps are similar to Maps but use weak references for keys, which can be beneficial in certain scenarios.

Keep in mind that the choice of data structure ultimately depends on your specific use case and performance requirements.

Related benchmarks:

Map vs Object v2 (version: 0)

Lookup of map vs object

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>

Fastest: N/A

Slowest: N/A

No previous run results

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