Let's dive into the world of JavaScript benchmarking.

What is being tested?

The provided JSON represents a benchmark test that compares three different approaches to assigning properties from one object to another:

1. Lodash assign: Using the _assign function from the Lodash library (a popular utility library for functional programming in JavaScript).
2. Object.assign: The built-in Object.assign method, which is a part of the ECMAScript 2015 (ES6) standard.
3. Spread operator: Using the spread syntax ({ ...object1, ...object2 }) to create a new object with properties from both objects.

What options are compared?

The three test cases compare different ways to assign properties from one object (b) to another (a):

• In each case, a and b are initialized as objects: var a = { a: 'oh', b: 'my' };\n var b = { c: 'goddess' };.
• The test cases then assign properties from b to a, using:
  • Lodash's _assign function (var c = _.assign(a, b);)
  • The built-in Object.assign method (var c = Object.assign(a, b);)
  • The spread operator syntax (var c = { ...a, ...b };)

Pros and Cons of each approach:

1. Lodash assign: Pros:
   • Easy to use and understand.
   • Works across different browsers and versions (including older ones).
   • Well-documented in the Lodash library. Cons:
     • Requires including an additional library (Lodash) in your project.
2. Object.assign: Pros:
   • A built-in method, so no extra library is needed.
   • Part of the ES6 standard, so widely supported.
   • Performs well for most use cases. Cons:
     • May have performance issues with very large objects or complex nesting (as seen in this benchmark).
3. Spread operator: Pros:
   • A concise and expressive syntax.
   • Works well with modern JavaScript environments.
   • No additional library needed. Cons:
     • May not be as performant as Object.assign for large datasets.

Other considerations:

• The spread operator ({ ...a, ...b }) is a newer feature in JavaScript (introduced in ES6) and may not work correctly in older browsers or environments.
• Lodash's _assign function provides more advanced features (like merging objects with arrays), which might be useful depending on your use case.

What library is used?

The lodash library is a popular utility library for functional programming in JavaScript. It provides various functions, including the _assign method, to make working with data structures easier and more efficient.

That's it!