Benchmark Overview

The provided JSON represents a JavaScript microbenchmarking test case on the MeasureThat.net website. The benchmark compares the performance of three different methods to merge two objects: the spread operator, Object.assign, and a custom merge method.

Options Compared

1. Spread Operator: Uses the syntax const finalObject = { ...firstObject, ...secondObject } to create a new object with merged properties.
2. Object.assign: Utilizes the Object.assign() method to merge two objects: const finalObject = Object.assign(firstObject, secondObject).
3. Custom Merge Method: Implements a custom merge function (merge) that recursively merges two objects.

Pros and Cons

1. Spread Operator:
   • Pros: Simple, concise syntax; does not require additional libraries.
   • Cons: May not be optimized for performance in certain situations (e.g., large object sizes).
2. Object.assign:
   • Pros: Widely supported and well-documented; can handle large objects efficiently.
   • Cons: Requires the Object global object, which might not be available in some environments.
3. Custom Merge Method:
   • Pros: Can provide more control over the merging process; potentially optimized for performance.
   • Cons: More complex syntax and implementation required.

Library/Functions Used

1. None explicitly mentioned in this benchmark. However, Object.assign() is a built-in function.

Special JS Features/Syntax

None explicitly used in this benchmark.

Benchmark Preparation Code Explanation

The script preparation code defines three objects (firstObject and secondObject) with some sample data, followed by the custom merge method implementation:

var firstObject = {
  sampleData: 'Hello world'
};

var secondObject = {
  moreData: 'foo bar'
};

var merge = (def, opt) => {
  // ... (custom merge function implementation)
};

Individual Test Cases

Each test case defines a different benchmark by using the corresponding method to merge firstObject and secondObject. The resulting final object is stored in a variable named finalObject.

1. Using the spread operator: const finalObject = { ...firstObject, ...secondObject }
2. Using Object.assign: const finalObject = Object.assign(firstObject, secondObject)
3. Using custom merge method (Create a clone object): const finalObject = merge(firstObject, secondObject)

Latest Benchmark Result Explanation

The benchmark results show the performance metrics for each test case on a Chrome 121 desktop running Linux:

1. Using the spread operator: 8640652 executions per second
2. Using Object.assign: 5470456 executions per second
3. Using custom merge method (Create a clone object): 1495925 executions per second

The results suggest that the spread operator is the fastest method, followed by Object.assign, and then the custom merge method.

Other Alternatives

1. Lodash.merge(): A popular utility library that provides a robust merging function.
2. Array.prototype.reduce(): Can be used to implement a custom merge function.
3. Recursive merge functions: Other approaches, like using JSON.parse() and JSON.stringify() to serialize the objects before merging them, might also be considered as alternatives.