Overview of the Benchmark

The provided benchmark, hosted on MeasureThat.net, compares the performance of three approaches for merging two objects: lodash's immutable merge (_.merge()), object.assign() (including an immutable version), and the spread operator ({ ...a, ...b }). The goal is to determine which approach is the fastest.

Options Compared

1. Lodash Immutable Merge: Uses the _. function from the Lodash library to perform an immutable merge.
2. Immutable Object Assign: Wraps object.assign() with a function that returns a new object, ensuring immutability.
3. Spread Operator: Utilizes the spread operator ({ ...a, ...b }) to create a new object by spreading the properties of two objects.

Pros and Cons of Each Approach

1. Lodash Immutable Merge
   • Pros:
     • Provides an immutable result.
     • Often used for its concise syntax.
   • Cons:
     • Requires including Lodash in the project, adding overhead.
     • May have slower performance due to library dependencies.
2. Immutable Object Assign
   • Pros:
     • Ensures immutability without relying on external libraries.
     • Can be faster since it doesn't introduce additional dependencies.
   • Cons:
     • The implementation can be more verbose than the spread operator.
3. Spread Operator
   • Pros:
     • Fast and concise syntax.
     • Does not require any external libraries or dependencies.
   • Cons:
     • May not provide explicit control over the merging process.

Library Used: Lodash

Lodash is a popular JavaScript utility library that provides a wide range of functions for tasks such as array manipulation, object manipulation, and more. The _.merge() function is specifically designed to merge two or more objects into one, ensuring immutability by default.

Special JS Feature/Syntax: None

There are no special JavaScript features or syntaxes used in this benchmark beyond the standard language features supported by all browsers.

Other Considerations

When choosing an approach for merging objects, consider the following factors:

• Immutability: Do you need to ensure that the merged object is immutable?
• Performance: Are speed and efficiency critical for your use case?
• Code Readability: How important is code readability and conciseness in your project?

Alternatives

If you're interested in exploring other options, consider:

1. Using Object.assign() without the wrapper function to achieve immutability.
2. Implementing a custom merge function using a library like Immutable.js or Ramda.
3. Utilizing other JavaScript libraries or frameworks that provide similar functionality.

Keep in mind that each alternative may have its own trade-offs and considerations, so be sure to evaluate them based on your specific needs and requirements.