Let's dive into the explanation.

Benchmark Description

The benchmark is called "Array concat vs spread operator vs push vs new array spread". It compares four different ways to concatenate two arrays in JavaScript: concat(), spread operator (...), push() with rest parameter, and creating a new array using the spread operator.

Test Cases

There are three test cases:

1. Array.prototype.concat: This test uses the traditional concat() method to merge two arrays.
   • Code snippet: other = other.concat(params);
   • Library/Language feature: None
   • Description: Simply concatenates two arrays using the concat() method.
2. Push: This test uses the push() method with rest parameter to add elements from one array to another.
   • Code snippet: other = other.push(...params);
   • Library/Language feature: None
   • Description: Uses the push() method with rest parameter to add elements from one array to another.
3. New array spread: This test uses the spread operator (...) to create a new array by spreading the contents of two arrays.
   • Code snippet: var other = [ ...other, ...params ];
   • Library/Language feature: Spread operator (...)
   • Description: Creates a new array by spreading the contents of two arrays using the spread operator.

Benchmark Results

The latest benchmark results show the execution speed (Executions Per Second) for each test case on Chrome 89:

1. Push: 30,568,930 executions per second
2. New array spread: 26,185,424 executions per second
3. Array.prototype.concat: 7,132,648 executions per second

Pros and Cons

• concat() method:
  • Pros: Easy to understand, widely supported.
  • Cons: Slow compared to other methods.
• Spread operator (...):
  • Pros: Fastest method in this benchmark, creates a new array without modifying the original arrays.
  • Cons: May cause performance issues if used excessively due to its overhead of creating a new array.
• push() with rest parameter:
  • Pros: Simple, easy to use. Modifies the original array.
  • Cons: Slow compared to spread operator.

Other Considerations

• If you need to concatenate arrays frequently, consider using the spread operator (...) for performance benefits.
• If you're working with large arrays and performance is critical, avoid using concat() or push() methods.
• The spread operator can also be used with objects, not just arrays.

Alternatives

If you don't want to use the spread operator or any of the above methods, you could consider:

1. Using Array.prototype.set() (ES2022) to update an array in place.
2. Implementing a custom concatenation function for performance-critical scenarios.
3. Avoiding complex operations on arrays and using other data structures instead (e.g., linked lists).