Benchmark Explanation

MeasureThat.net is testing the performance difference between two ways to concatenate arrays in JavaScript: using the concat() method and the spread operator (...).

The benchmark compares these two approaches on an example dataset containing a string, a boolean, and an integer. The goal is to determine which approach is faster.

Options Comparison

There are two options being compared:

1. Array.prototype.concat: This method takes two or more arrays as arguments and returns a new array that contains all the elements from the original arrays.
2. Spread operator (...): This operator allows you to expand an array into individual elements, which can then be used in a function call.

Pros and Cons of Each Approach

• Array.prototype.concat:
  • Pros:
    • Well-supported across most browsers
    • Easy to read and understand for developers familiar with the method
  • Cons:
    • Can lead to unnecessary memory allocations, potentially causing performance issues
    • May not be as efficient as the spread operator in modern JavaScript engines
• Spread operator (...):
  • Pros:
    • Generally faster than concat() due to reduced overhead
    • More concise and readable for many developers
  • Cons:
    • Not supported in older browsers (e.g., Internet Explorer)
    • May require additional syntax changes for some developers

Library Consideration

None of the benchmark test cases use any external libraries. The JavaScript core functions (Array.prototype.concat and the spread operator) are being tested.

Special JS Features/Syntax

The benchmark uses the ES6 spread operator (...). This feature was introduced in ECMAScript 2015 (ES6) and allows for more concise array expansion.

Other Alternatives

Alternative approaches to concatenate arrays could include:

1. Using Array.prototype.push() with an array as an argument
2. Using Array.prototype.set() (although this is not a standard method and may not be supported in all browsers)
3. Creating a new array using the Array constructor and iterating over the elements from the original arrays

Keep in mind that these alternatives might have different performance characteristics or syntax requirements compared to the spread operator.

Benchmark Preparation Code

The provided code snippet is a minimal example, likely created for benchmarking purposes:

var params = [ "hello", true, 7 ];
var other = [ 1, 2 ].concat(params);

And similarly for the spread operator test case:

var params = [ "hello", true, 7 ]
var other = [ 1, 2, ...params ];

These examples illustrate how to concatenate arrays using the two tested approaches.