Benchmark: Map vs Object set value

Script Preparation code:

var map = new Map();
var obj = {};
var randomU32 = function() {
	return Math.random() * (1 << 31) >>> 0;
}

Tests:

Map
map.set(randomU32(), true);
Object
obj[randomU32()] = true;

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Map
Object

Fastest: N/A

Slowest: N/A

Latest run results:

No previous run results

This benchmark does not have any results yet. Be the first one to run it!

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

LLMs can make mistakes. Check important info.

Let's dive into the explanation of the provided benchmark.

**What is being tested?**

The benchmark measures the performance difference between using a `Map` data structure and an object (`{}`) to store boolean values, specifically when setting a value on a randomly generated key. The test case checks how fast each approach can set a value on its respective data structure.

**Options compared:**

Two main options are being compared:

1. **`Map.set()`**: This method sets the value of the specified key in the map to the given value. In this benchmark, it's used to set a boolean value `true` for a random key generated by the `randomU32()` function.
2. **`obj[key] = true`**: This is using an object literal (`{}`) and setting the value of a property on the object with a randomly generated key.

**Pros and Cons:**

**Map.set():**

Pros:

* Efficient use of memory, as only the necessary data is stored
* Fast lookups and insertions

Cons:

* May have slower startup times due to map initialization
* Can be slower for very large datasets due to the overhead of internal data structures

**obj[key] = true**:

Pros:

* Simple and straightforward syntax
* Faster startup times, as no additional data structure is required

Cons:

* Inefficient use of memory, as all keys must be stored in an object literal
* Slow lookups and insertions due to the need to access every property on the object

**Other considerations:**

Both approaches have their trade-offs. `Map.set()` offers faster performance for large datasets but requires more overhead during initialization. On the other hand, `obj[key] = true` is simpler to understand and implement but uses more memory.

**Library/Dependency:**

There is no explicit library or dependency mentioned in the benchmark definition. However, it's worth noting that if the benchmark were using a custom library for either of these approaches, it would impact the results.

**Special JS feature/syntax:**

The `>>> 0` syntax used in the `randomU32()` function is a bitwise right shift operation to ensure the result is a non-negative integer. This syntax relies on the ECMAScript specification and is not specific to any particular browser or version.

I hope this explanation helps software engineers understand the benchmark and its underlying mechanics!

Related benchmarks:

Map vs Object set value (version: 0)

Comparing performance of: Map vs Object

Created: 3 years ago by: Guest

Jump to the latest result

Map

Object

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):