Benchmark Overview

MeasureThat.net is a website that allows users to create and run JavaScript microbenchmarks. The provided benchmark measures the performance of three different approaches for creating an object with merged data: using the spread operator (...), Object.assign, and mutation (direct assignment).

Options Compared

1. Using the Spread Operator: This approach uses the spread operator (...) to merge two objects into a new object.
2. Using Object.assign: This approach uses the Object.assign() method to merge two objects into a new object.
3. Mutation: This approach directly assigns properties from one object to another, without creating a new object.

Pros and Cons

• Using the Spread Operator:
  • Pros: concise syntax, easy to read and write.
  • Cons: may not work in older browsers that don't support spread operator, can be slower due to function call overhead.
• Using Object.assign:
  • Pros: widely supported across browsers, can be faster than spread operator due to method call optimization.
  • Cons: less readable syntax compared to spread operator, may require more lines of code.
• Mutation:
  • Pros: fast and lightweight, no additional function calls required.
  • Cons: less readable and maintainable, can lead to bugs if not done carefully.

Library

The Object.assign() method is a built-in JavaScript library that is widely supported across browsers. It allows you to merge multiple objects into a single object, overwriting any existing properties with the same key.

Special JS Features or Syntax

The spread operator (...) is a new feature introduced in ECMAScript 2018 (ES2018) and later versions. It allows you to expand an array or object into a new object, making it easier to merge data.

Benchmark Result Interpretation

The latest benchmark result shows the execution per second for each approach:

• Mutation: 623631424 executions per second
• Using the spread operator: 43871344 executions per second
• Using Object.assign: 13334525 executions per second

This suggests that mutation is the fastest approach, followed by using the spread operator, and then Object.assign.

Other Alternatives

If you don't want to use the spread operator or Object.assign, you can also consider other alternatives:

1. Loose Equal Operator (==): This method is less readable and may lead to bugs due to type coercion.
2. Constructor Function: You can create a constructor function for an object and then call it with the desired properties, but this approach is less efficient than mutation.
3. Array-like Objects: You can use array-like objects like Array.prototype.slice() or Object.keys() to merge data, but these approaches are more complex and may not be as readable.

In general, the spread operator and Object.assign are good choices for merging objects due to their readability and maintainability. Mutation is a fast alternative, but it requires careful consideration of potential bugs and edge cases.