Benchmark: set.has vs. array.includes Perf Random 1

Script Preparation code:

var a = Array.from({length: 100}, () => Math.floor(Math.random() * 40));
var b = new Set(a);

Tests:

Includes
return a.includes(98)
lookup
return b.has(98)

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Includes
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.

I'll break down the explanation into smaller parts to make it easier to understand.

**Benchmark Definition and Script Preparation Code**

The provided JSON represents a JavaScript benchmark that tests the performance of two different approaches: `array.includes` and `set.has`. The script preparation code initializes two arrays:

*   `a`: An array with 100 elements, where each element is a random number between 0 and 39 (inclusive).
*   `b`: A Set created from array `a`.

The purpose of creating these two data structures is to provide a common baseline for the benchmark. The set `b` serves as a container for unique values extracted from array `a`, which will be used in the subsequent test cases.

**Test Cases**

There are two individual test cases:

1.  **Includes**: This test case uses the `array.includes` method to search for a specific value (98) within array `a`. The goal is to measure the performance of this method.
2.  **lookup**: This test case uses the `set.has` method to check if a specific value (98) exists in set `b`. Again, the objective is to evaluate the performance of this approach.

**Library and Special JS Features**

In both test cases:

*   A library called `Array.from()` is used to create an array with 100 random numbers. This function is a modern JavaScript method for creating arrays from iterables.
*   The use of `Math.floor(Math.random() * 40)` generates random numbers between 0 and 39 (inclusive). This is a common way to generate random values in JavaScript.

**Pros and Cons**

Here's a brief analysis of the two approaches:

*   **array.includes**:
    *   Pros:
        +   Widely supported across browsers.
        +   Relatively fast due to its optimized implementation.
    *   Cons:
        +   Can be slower for large arrays or searching for specific values near the end of the array.
        +   May perform poorly if the array contains duplicate values (since it has to linearly search through the array).
*   **set.has**:
    +   Pros:
        - Fast and efficient, especially for unique values.
        - Can be faster than `array.includes` when searching for specific values near the beginning of the set.
    *   Cons:
        - Not as widely supported across browsers (it's a newer feature).
        - Requires the array or set to be created first.

**Other Alternatives**

Some alternative approaches could have been used:

*   For `array.includes`, you could use the `indexOf()` method, which returns the index of the specified value. If the value is not found, it returns `-1`.
*   For `set.has`, a more traditional approach would be to use the `hasOwnProperty()` method or the `in` operator with an object.

Keep in mind that these alternatives might have slightly different performance characteristics compared to the original methods used in the benchmark.

Related benchmarks:

set.has vs. array.includes Perf Random 1 (version: 0)

set.has vs. array.includes Perf Random 1

Comparing performance of: Includes vs lookup

Created: 4 years ago by: Guest

Jump to the latest result

Includes

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):