Benchmark: Map vs Object access and check

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'); const exists = map.has('a') }
Obj lookup
for (i = 0; i < count; i++) { a = obj['a']; const exists = 'a' in obj; }

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's being tested.

**What is being tested?**

The benchmark compares two approaches to look up values in JavaScript:

1. **Object (Obj) lookup**: Using the `['a']` syntax to access an object property, followed by a check using `'a' in obj`.
2. **Map (Map) lookup**: Using the `map.get('a')` method to directly retrieve a value from a Map instance.

**Options compared**

The benchmark is comparing two options:

1. Object lookup (`Obj lookup`)
2. Map lookup (`Map lookup`)

**Pros and Cons of each approach:**

* **Object lookup (Obj lookup)**:
	+ Pros:
		- Widely supported in JavaScript engines.
		- Easy to read and write.
	+ Cons:
		- Can be slower due to the additional step of checking for existence (`'a' in obj`).
* **Map lookup (Map lookup)**:
	+ Pros:
		- Can be faster than object lookup, especially when dealing with large datasets.
		- Provides a more efficient way to store and retrieve data using keys.
	+ Cons:
		- Requires the use of a Map instance, which may not be as familiar to some developers.

**Special JS feature or syntax**

There is no special JavaScript feature or syntax being tested in this benchmark. The focus is on comparing two fundamental approaches to look up values in JavaScript.

**Other alternatives**

If you were to compare other approaches to object lookup and map lookup, some possible alternatives could be:

* **Array indexing**: Instead of using object properties or Map keys, you might use array indices to access data.
* **Prototype chaining**: You might use prototype chaining to traverse objects and access nested properties.
* **Native methods**: Depending on the JavaScript engine, there may be native methods available for lookups, such as `Object.prototype.hasOwnProperty.call()`.

However, these alternatives are not part of this specific benchmark, which is focused on comparing object lookup and map lookup.

Related benchmarks:

Map vs Object access and check (version: 0)

Lookup of map vs object

Comparing performance of: Map lookup vs Obj lookup

Created: 6 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):