In this benchmark, the performance of three different methods for creating a deep copy of a complex JavaScript object is compared. The three approaches being tested are:

1. Lodash's cloneDeep:

   • Syntax: myCopy = _.cloneDeep(myObject);
   • Library: Lodash is a popular JavaScript utility library providing various functions for common programming tasks such as manipulating and iterating arrays, numbers, objects, strings, etc. The cloneDeep function specifically is used to create a deep copy of a value, which means that it recursively clones every object, including nested objects.
   • Pros:
     • Handles cloning of complex and nested structures well.
     • Robust against various data types (like dates, functions, and arrays).
   • Cons:
     • Larger footprint in terms of file size and often slower compared to native methods.
     • Introduces an additional dependency in the application.

2. JSON Serialization:

   • Syntax: myCopy = JSON.parse(JSON.stringify(myObject));
   • Mechanism: This method converts the object to a JSON string and then parses it back to an object, effectively creating a deep clone.
   • Pros:
     • Very simple and doesn’t require any additional libraries.
     • Fast for basic objects.
   • Cons:
     • Cannot handle functions, undefined values, symbols, or complex types like dates or sets, leading to loss of data integrity if such types are present.
     • May result in performance issues with very large objects due to JSON serialization overhead.

3. Structured Clone:

   • Syntax: myCopy = structuredClone(myObject);
   • Feature: The structuredClone method is a newer addition to JavaScript that allows for cloning values that can include more complex types.
   • Pros:
     • Native method, which means it’s fast and generally more efficient than other methods.
     • Supports a wide range of built-in types including Maps, Sets, and even cyclical references.
   • Cons:
     • As of the time of writing, browser support may be limited compared to other established methods (but support has been improving).
     • Relatively new, which might introduce inconsistencies in some environments.

Benchmark Results

The benchmark results indicate the number of executions per second for each cloning method on a specified browser and operating system environment:

• JSON Clone: 345,872.25 executions per second
• Lodash CloneDeep: 267,002.0 executions per second
• Structured Clone: 234,659.625 executions per second

Summary of Findings

• The JSON serialization method shows the highest performance in this specific benchmark, which suggests that for simple data types, it might be the best option in terms of speed.
• The Lodash cloneDeep method, while slower, provides robustness in handling complex objects and unexpected data types.
• The structuredClone function, while native and very versatile, came in the lowest for this specific test case, indicating that while it is useful, its performance may not always match that of the other methods.

Alternatives

Other potential alternatives for deep cloning include:

• Manual deep cloning: Writing a custom recursive function to clone objects. This gives developers complete control but can be error-prone and tedious.
• Using the spread operator in conjunction with shallow copy techniques: This method is limited to one level deep.
• Third-party libraries: Apart from Lodash, libraries such as rfdc (Really Fast Deep Clone) are designed specifically for high-performance deep cloning.

Overall, the choice of method can depend on the complexity of the data being cloned, the need for performance, and the specific requirements of the application.