Benchmark: Map vs Object (counter inc)

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++) { map.set('a', +map.get('a') + 1); }
Obj lookup
for (i = 0; i < count; i++) { obj['a'] += 1; }

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 benchmark and explain what is being tested, compared, and analyzed.

**What is being tested?**

The benchmark measures the performance difference between using a `Map` data structure and an object (`obj`) to store and increment a counter value.

**Options compared:**

Two options are compared:

1. **Object lookup**: The code increments the counter value by 1 using the syntax `obj['a'] += 1;`. This uses the dot notation to access the 'a' property of the obj object.
2. **Map lookup**: The code increments the counter value by 1 using the syntax `map.set('a', +map.get('a') + 1);`. This uses the `set` method of the Map object to add a new entry with key 'a' and value incremented from the existing value.

**Pros and Cons:**

* **Object lookup (dot notation)**:
	+ Pros:
		- Easy to read and write, as it follows the conventional property access syntax.
		- May be more intuitive for developers familiar with JavaScript objects.
	+ Cons:
		- Can lead to slower performance due to string concatenation and indirect property access.
		- Does not handle property access errors explicitly, which can cause unexpected behavior.
* **Map lookup (set method)**:
	+ Pros:
		- Provides direct access to the value associated with a key, without the need for concatenation or dot notation.
		- Allows for explicit handling of property access errors using try-catch blocks.
	+ Cons:
		- Requires more code and may be less intuitive for developers unfamiliar with Maps.

**Library:**

The `Map` object is used in this benchmark. A Map is a data structure that stores key-value pairs, where each key is unique and maps to a specific value. It provides efficient lookup, insertion, and deletion operations.

**Special JavaScript feature:**

None mentioned in the provided code snippet.

**Other alternatives:**

There are other ways to increment a counter value in JavaScript:

* Using an array or object with numeric keys: `var countArray = [0]; countArray[0]++;`
* Using a library like Lodash's `assignIn` function: `_count += 1; _count = assignIn(_count, {a: 5});`

However, the benchmark is focused on comparing the performance of using an object and a Map to store and increment a counter value.

Related benchmarks:

Map vs Object (counter inc) (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

No previous run results

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