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

Test name	Executions per second
set.has	497031648.0 Ops/sec
key lookup	291736704.0 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.

Related benchmarks:

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

Comparing performance of: set.has vs key lookup

Created: 2 years ago by: Guest

Jump 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):