Benchmark: set.has vs. Object

Script Preparation code:

var a = new Set([1, 2, 3, 4, 5, 6, 7, 8, 9, 10]);
var b = {1: true, 2: true, 3: true, 4: true, 5: true, 6: true, 7: true, 8: true, 9: true, 10: true}

Tests:

sett
return a.has(9)
key lookup
return !!b['9']

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
sett
key 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 dive into the world of JavaScript microbenchmarks on MeasureThat.net.

**Benchmark Definition JSON**

The provided JSON represents a benchmark that tests two different approaches to check if an element exists in a Set or an object.

The `Script Preparation Code` section defines two variables: `a`, which is a new Set created with 10 elements, and `b`, which is an object with the same elements as the Set. The purpose of this code is to create a concrete scenario for testing the performance of accessing elements in these data structures.

**Options Compared**

In this benchmark, two options are compared:

1. **`a.has(9)`**: This approach uses the `has()` method on the Set `a`, which checks if an element with the value 9 exists in the set.
2. **`!!b['9']`**: This approach uses a trick to check if an element with the key '9' exists in the object `b`. The double exclamation mark (`!!`) is used to convert the result of the property access to a boolean value.

**Pros and Cons**

Here's a brief analysis of each approach:

1. **`a.has(9)`**
	* Pros: Simple, straightforward, and efficient for checking membership in a Set.
	* Cons: May incur additional overhead due to the use of a method call.
2. **`!!b['9']`**
	* Pros: Elegant, concise, and avoids the overhead of a method call.
	* Cons: Less readable and may be slower due to the property access operation.

**Library Usage**

In this benchmark, no external libraries are used.

**Special JS Features or Syntax**

None mentioned in the provided code.

**Other Considerations**

When writing benchmarks like this one, it's essential to consider factors such as:

* **Repeatability**: Are the results consistent and repeatable?
* **Consistency**: Is the benchmark executed consistently across different runs and browsers?
* **Overhead**: Are there any external factors (e.g., network latency) that could impact performance?

**Alternatives**

If you're looking for alternative approaches to access elements in a Set or an object, consider:

1. Using `in` operator instead of `has()` for Sets.
2. Using the `hasOwnProperty()` method on objects instead of property access (`b['9']`).
3. Implementing your own membership test using bitwise operations (e.g., `a.has(9)` can be implemented as `!!((a >> 0) & (1 << 9))`).

Keep in mind that the best approach will depend on the specific requirements of your use case and performance characteristics.

Related benchmarks:

set.has vs. Object (version: 0)

Comparing performance of: sett vs key lookup

Created: 3 years ago by: Guest

Jump to the latest result

sett

key 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):