Benchmark: remove duplicates from array

Tests:

a
let a=[1,1,2,2,3,3,4,4,5,5] function uniq_fast(a) { var seen = {}; var out = []; var len = a.length; var j = 0; for(var i = 0; i < len; i++) { var item = a[i]; if(seen[item] !== 1) { seen[item] = 1; out[j++] = item; } } return out; } console.log(uniq_fast(a));
b
let a=[1,1,2,2,3,3,4,4,5,5] function uniq(a) { return Array.from(new Set(a)); } console.log(uniq(a));
c
let a=[1,1,2,2,3,3,4,4,5,5] let uniq = a => [...new Set(a)]; console.log(uniq(a));

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
a
b
c

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 27 days ago):

LLMs can make mistakes. Check important info.

Measuring performance and identifying the most efficient approach for specific tasks is crucial in software development.

**What is being tested?**

The provided JSON represents three individual test cases for removing duplicates from an array. The task is to write a function that takes an array as input, removes any duplicate elements, and returns the resulting array.

**Options compared:**

1.  **Manual implementation with a set data structure:** This approach uses a set to keep track of unique elements encountered so far. It iterates through the array, adding each element to the set if it's not already present.
2.  **Using Array.prototype.from() and Set():** This approach utilizes built-in methods to convert an array into a set (which automatically removes duplicates) and then converts it back into an array using Array.from().
3.  **Arrow function with spread operator:** Similar to the second option, this uses an arrow function that takes an array as input, creates a new set from it, and returns the resulting array.

**Pros and Cons:**

1.  **Manual implementation with a set data structure:**
    *   Pros:
        *   Control over memory allocation and manipulation
        *   Suitable for small arrays or specific performance-critical scenarios
    *   Cons:
        *   More complex to implement, especially for developers without prior experience with sets
        *   Potential performance overhead due to explicit set creation and iteration
2.  **Using Array.prototype.from() and Set():**
    *   Pros:
        *   Built-in methods reduce the likelihood of errors or implementation pitfalls
        *   Faster execution since these operations are optimized by the browser
    *   Cons:
        *   Less control over memory allocation and manipulation
3.  **Arrow function with spread operator:**
    *   Pros:
        *   Concise syntax, making it easier to understand for developers familiar with JavaScript arrow functions
        *   Similar performance profile as the second option
    *   Cons:
        *   Less explicit control over memory allocation and manipulation

**Library considerations:**

None of the provided test cases explicitly use a library. However, if a developer were to implement their own solution using external libraries, they might choose the following options:

*   **lodash**: Provides an implementation for `uniq` that is optimized for performance.
*   **Ramda**: Offers several functions related to array manipulation and filtering, including potentially something similar to `uniq`.
*   **ES6 built-in methods**: Although not explicitly mentioned in this example, a developer might use the `Set()` data structure or other methods like `reduce()`.

**Special JS feature/syntax:**

None of the provided test cases include special JavaScript features or syntax. They primarily utilize standard JavaScript constructs for array manipulation and set operations.

**Benchmark results analysis:**

The benchmark result shows that each approach has different execution frequencies across multiple runs:

*   **Manual implementation with a set data structure:** The highest execution frequency is observed, indicating this might be the most efficient method among the three options.
*   **Using Array.prototype.from() and Set():** The second-highest execution frequency suggests this approach also performs well but slightly worse than the manual implementation.
*   **Arrow function with spread operator:** The lowest execution frequency indicates that this method might have performance overhead compared to the other two options.

Keep in mind that actual results may vary depending on factors like the size of the input array, specific hardware configuration, and possible variations in browser implementations.

**Other alternatives:**

For this problem, additional solutions could include:

*   **Using a custom implementation with a different data structure:** Depending on performance requirements, developers might choose an alternative data structure like a hash map or trie for duplicate removal.
*   **Employing parallel processing techniques:** If the array is very large and execution time is critical, using parallelization to concurrently process subsets of the array could offer potential benefits.

In general, when working with performance-critical code in JavaScript, understanding how different methods execute, identifying bottlenecks, and optimizing accordingly can lead to significant improvements.

Latest run results:

Run details: (Test run date: 2 years ago)

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:104.0) Gecko/20100101 Firefox/104.0

Browser/OS: Firefox 104 on Windows

View result in a separate tab

Test name	Executions per second
a	135116.4 Ops/sec
b	121865.2 Ops/sec
c	124179.4 Ops/sec

Related benchmarks:

remove duplicates from array (version: 0)

Comparing performance of: a vs b vs c

Created: 2 years ago by: Guest

Jump to the latest result

a

b

c

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 27 days ago):