Benchmark: set.has vs. Object key lookup for real without bang bang

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/605.1.15 (KHTML, like Gecko) Version/17.3.1 Safari/605.1.15

Browser/OS: Safari 17 on Mac OS X 10.15.7

View result in a separate tab

set.has

497.0M/s

key lookup

291.7M/s

View exact numbers

Test name	Executions per second
✓ set.has	497,031,648 Ops/sec
key lookup	291,736,704 Ops/sec

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

LLMs can make mistakes. Check important info.

Let's break down the provided benchmark and explain what is being tested, compared, and discussed.

**Benchmark Definition JSON**

The benchmark definition provides two scripts that are used to test different approaches for finding an element in a Set (a collection of unique values) versus looking up a key in an Object.

1. **Script Preparation Code**: This code creates a new Set `a` containing numbers from 1 to 10, and another object `b` with the same keys as the set but with values that indicate presence (true) or absence (false).
2. **Html Preparation Code**: There is no HTML preparation code provided in this benchmark definition.

**Individual Test Cases**

The test cases are designed to measure the performance of two different approaches:

1. **Test Name: "set.has"**: This test case uses the `has()` method on the Set `a` to check if a specific value (9) is present.
2. **Test Name: "key lookup"**: This test case uses object property access (`b['9']`) to look up the value associated with key 9 in the object `b`.

**Comparison**

In this benchmark, we have two approaches being compared:

* Using the `has()` method on a Set
* Looking up a key in an Object using bracket notation

The test cases aim to measure which approach is faster and more efficient for finding a specific value or checking presence in a collection.

**Pros and Cons of Each Approach**

1. **Set.has() Method**: Pros:
	* Fast lookup with average O(1) time complexity
	* Can be used to check for presence (i.e., if an element exists in the Set)
Cons:
	* Not designed for key-value lookups; might require additional operations to achieve this
2. **Object Key Lookup**: Pros:
	* Can be used for key-value lookups
	* Allows accessing values associated with specific keys
Cons:
	* Slower lookup with average O(1) time complexity, especially if the object is large or has many keys
	* May not provide an immediate indication of presence (i.e., checking `b['9']` might return undefined if the key doesn't exist)

**Library and Syntax**

The Set data structure and its methods (`has()`) are built into JavaScript. No additional library is required for this benchmark.

No special JS features or syntax are used in this benchmark.

**Other Alternatives**

If you need to find a specific value in a collection, consider using other data structures like:

* Arrays (using `indexOf()` or a binary search algorithm)
* Maps (if you need key-value lookups with fast access times)

For checking presence in a collection, Set is still an efficient and recommended approach.

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

set.has vs. Object key lookup for real without bang bang (version: 0)

Comparing performance of: `set.has vs key lookup`

Created: 3 years ago by: Guest

Go to the latest result

set.has

key lookup

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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

set.has vs. Object key lookup for real without bang bang (version: 0)

Comparing performance of: set.has vs key lookup

Created: 3 years ago by: Guest

Go to the latest result

set.has

key lookup

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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

Related benchmarks

Comparing performance of: `set.has vs key lookup`