Let's break down the benchmark and its components.

Benchmark Definition

The benchmark is designed to compare two approaches for removing duplicates from an array: Lodash's uniq function and JavaScript's built-in Set object.

Options Compared

Two options are being compared:

1. Lodash Uniq: This uses the uniq function from the Lodash library, which removes duplicate elements from an array.
2. JavaScript Set: This uses the Set object in JavaScript, which automatically removes duplicates when used with arrays.

Pros and Cons

• Lodash Uniq:
  • Pros: Easy to use, well-documented, and widely adopted.
  • Cons: Adds extra overhead due to the library, may not be suitable for very large datasets.
• JavaScript Set:
  • Pros: Native implementation, lightweight, and efficient.
  • Cons: May require more manual effort to implement correctly, especially for large datasets.

Library and Purpose

The lodash library is a popular JavaScript utility belt that provides various functions for tasks like array manipulation, string manipulation, and more. In this case, the uniq function is used to remove duplicates from an array.

Special JS Feature or Syntax

None are mentioned in the provided code. However, it's worth noting that some JavaScript versions have had experimental features or syntaxes related to sets, but these were not widely adopted until recent versions of the language.

Other Alternatives

Besides Lodash and JavaScript Set, other alternatives for removing duplicates from an array include:

• Using Array.prototype.filter() and keeping track of unique elements in an external data structure.
• Utilizing a library like underscore (similar to Lodash) or ramda.
• Implementing a custom solution using only built-in JavaScript functions.

Benchmark Preparation Code

The script preparation code generates two arrays with 10,000 elements each. These arrays are then used as input for both benchmark tests.

Individual Test Cases

Each test case runs the specified function on the generated array:

1. Lodash Uniq: The uniq function from Lodash is called on the combined array (arrayToDedup).
2. JavaScript Set: A new Set object is created from the combined array, and its size (i.e., the number of unique elements) is obtained.

Latest Benchmark Result

The latest benchmark result shows that the JavaScript Set approach outperforms Lodash Uniq in terms of executions per second on a Chrome 89 browser running on Windows.