Benchmark: Map vs Object performance

Script Preparation code:

var map = new Map();
var obj = {};

map.set('a', 5);
obj['a'] = 5;

var i = 0, count = 100000, a;

Tests:

Map lookup
for (i = 0; i < count; i++) { a = map.get('a'); }
Obj lookup
for (i = 0; i < count; i++) { a = obj['a']; }
Map set
for (i = 0; i < count; i++) { map.set('b', i); }
Obj set
for (i = 0; i < count; i++) { obj['b'] = i; }

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Map lookup
Obj lookup
Map set
Obj set

Fastest: N/A

Slowest: N/A

Latest run results:

No previous 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 benchmark and its test cases.

**Benchmark Definition**

The benchmark is designed to compare the performance of two data structures: Maps (also known as Hash Tables) and Objects in JavaScript. The specific comparison is between looking up values in a Map versus an Object, and also between setting key-value pairs in both data structures.

**Options Compared**

There are four test cases:

1. **Map lookup**: This test case checks the performance of looking up a value in a Map using the `get()` method.
2. **Object lookup**: This test case checks the performance of looking up a value in an Object using bracket notation (`obj['a']`).
3. **Map set**: This test case checks the performance of setting a key-value pair in a Map using the `set()` method.
4. **Object set**: This test case checks the performance of setting a key-value pair in an Object using bracket notation (`obj['b'] = i;`).

**Pros and Cons**

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

1. **Map lookup (get())**:
	* Pros: Fast, especially for large datasets.
	* Cons: May incur additional overhead due to the `get()` method being called on the Map.
2. **Object lookup (bracket notation)**:
	* Pros: Simple and straightforward, with minimal overhead.
	* Cons: Can be slower than using a Map for large datasets.
3. **Map set**:
	* Pros: Fast and efficient for setting key-value pairs.
	* Cons: May not be suitable for looking up values, as it only sets the value without checking if the key exists.
4. **Object set**:
	* Pros: Simple and straightforward, with minimal overhead.
	* Cons: Can be slower than using a Map for large datasets.

**Libraries Used**

None of the test cases use any external libraries.

**Special JS Features/Syntax**

There are no special JavaScript features or syntax used in these benchmark tests. The code is standard JavaScript, with no advanced features like async/await, Promises, or modern ES6+ syntax.

**Alternatives**

If you're interested in exploring alternative data structures or approaches for performance-critical code, here are a few options:

* **JSON objects**: Instead of using Maps and Objects, you could use JSON objects as an alternative. However, this would likely incur significant overhead due to the need to serialize and deserialize the data.
* **WeakMaps**: If you're working with large datasets and don't need to store arbitrary data, WeakMaps might be a good alternative. They provide similar performance characteristics to Maps but are more lightweight.
* **IndexedDB or other persistent storage solutions**: For storing large amounts of data, consider using IndexedDB or other persistent storage solutions like Web Storage or LocalStorage.

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

Related benchmarks:

Map vs Object performance (version: 0)

Lookup of map vs object

Comparing performance of: Map lookup vs Obj lookup vs Map set vs Obj set

Created: 3 years ago by: Guest

Jump to the latest result

Map lookup

Obj lookup

Map set

Obj set

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):