Benchmark: set.has(key) vs. Boolean(obj[key])

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:

set.has()
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
set.has()
key lookup

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: one year ago)

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/108.0.0.0 Safari/537.36

Browser/OS: Chrome 108 on Mac OS X 10.15.7

View result in a separate tab

Test name	Executions per second
set.has()	28303836.0 Ops/sec
key lookup	28103882.0 Ops/sec

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

LLMs can make mistakes. Check important info.

Let's break down the provided benchmark and explain what's being tested.

**Benchmark Definition**

The benchmark is defined by two test cases:

1. `set.has(key)`: This test case checks the performance of the `has()` method on a `Set` object. A `Set` in JavaScript is an unordered collection of unique values, which makes it efficient for adding and removing elements.
2. `Boolean(obj[key])`: This test case checks the performance of accessing a key in an object (`obj`) using the `Boolean` function.

**Options Compared**

The two options being compared are:

* Using the `has()` method on a `Set` object
* Using the `Boolean` function to access a key in an object

These two approaches differ in how they handle null or undefined keys. The `set.has(key)` approach throws an error if the key is not present, whereas the `Boolean(obj[key])` approach returns `false`.

**Pros and Cons of Each Approach**

* `set.has(key)`: Pros:
	+ Efficient for large sets
	+ Simple and straightforward implementation
Cons:
	+ Throws an error if the key is not present, which can lead to unexpected behavior in some cases
* `Boolean(obj[key])`: Pros:
	+ Returns a boolean value for any key (even if it's not present)
	+ Does not throw an error if the key is not present
Cons:
	+ May be slower due to the overhead of the `Boolean` function and the object lookup

**Library and Purpose**

In this benchmark, no libraries are explicitly mentioned. However, the use of a `Set` object implies that JavaScript's built-in `Set` type or a similar data structure is being used.

**Special JS Feature/Syntax**

There is no special JavaScript feature or syntax being used in this benchmark. The code is straightforward and standard JavaScript.

**Other Alternatives**

If you were to compare the performance of these two approaches, you could also consider other alternatives, such as:

* Using `Object.prototype.hasOwnProperty.call()` (a more traditional approach)
* Using a custom function to check if a key is present in an object
* Using a data structure like a trie or a prefix tree

Keep in mind that the choice of approach depends on the specific requirements and constraints of your use case.

**Benchmark Preparation Code**

The preparation code for this benchmark creates two objects:

* `a`: An empty `Set` object initialized with some values.
* `b`: An object with keys 1-10, each assigned a boolean value of `true`.

These objects are then used as inputs for the test cases.

Related benchmarks:

set.has(key) vs. Boolean(obj[key]) (version: 0)

Comparing performance of: set.has() vs key lookup

Created: one year ago by: Guest

Jump to the latest result

set.has()

key lookup

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

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