The benchmark you provided focuses on comparing two different approaches for computing the union of two arrays in JavaScript: one using the Lodash library and the other utilizing the native JavaScript Set object.

Benchmark Overview

• Name: "Lodash union vs new Set() union"
• Description: Not provided, but it aims to compare the performance of two implementations that achieve the same outcome: creating a union of two arrays.
• Libraries Used: Lodash, a popular JavaScript utility library that simplifies common tasks such as manipulation and traversal of arrays, objects, and strings.

Test Cases Explained

1. Lodash Union Test Case

   • Benchmark Definition:

     const c = _.union(a, b);
     

     This code uses Lodash’s _.union function to find the unique elements from two arrays a and b. Lodash handles the uniqueness internally and combines the two arrays efficiently.
   • Advantages:
     • Ease of Use: The syntax is straightforward and does not require deep knowledge of the underlying data structures.
     • Robustness: Lodash is well-tested and often optimized for performance in different environments.
   • Disadvantages:
     • Dependency: It adds the overhead of including the Lodash library into your project which increases bundle size.
     • Potential Overhead: For simple operations, there may be slight performance overhead due to abstractions provided by the library.

2. New Set() Union Test Case

   • Benchmark Definition:

     const setA = new Set(a);
     const setB = new Set(b);
     const c = setA.union(setB);
     

     This attempts to create a Set from both arrays a and b and calls a non-existent union() method. The correct approach would involve merging the sets manually. For example:

     const c = [...setA, ...setB];
     

     Using Set is beneficial because it inherently handles uniqueness, ensuring that duplicates are removed.
   • Advantages:
     • No Dependencies: Native Sets are part of the standard JavaScript specification, so no external libraries are required.
     • Performance: Generally faster for native operations since it utilizes built-in JavaScript features.
   • Disadvantages:
     • Method Limitation: As observed, Set does not provide a built-in union method; users must implement their logic to combine sets, effectively rising complexity.
     • Manual Handling: Requires additional steps for union operations compared to using a library function.

Performance Results

From the benchmark results, we can observe the execution speed of both approaches on Chrome 131.

• Lodash Union
  • Executions Per Second: 3,862,328.5
• New Set() Union
  • Executions Per Second: 2,896,312.25

Conclusions

• Lodash shows better performance in this specific benchmark despite its dependency overhead, likely due to its optimized handling of array union operations.
• Set requires proper union handling, but is more performant than Lodash in a straightforward comparison without considering the non-existent method invocation error.

Alternatives

• Spread Operator and Array Methods: You can manually compute the union using a combination of the spread operator and methods like filter() in conjunction with includes().
• Other Libraries: There are alternatives to Lodash, such as Underscore.js, but they typically provide similar functionalities. Proposals like Ramda also offer functional programming techniques but may have different trade-offs regarding performance and usability.

Overall, when performing operations involving unions or array manipulations, it is essential to consider the complexity of the operation, the need for dependencies, maintainability of the code, and testing for performance in your specific environment.