Let's dive into the world of MeasureThat.net and explore what's being tested in this benchmark.

What is being tested?

MeasureThat.net is a platform for creating and running JavaScript microbenchmarks. The provided JSON represents two test cases, each with a unique approach to testing a specific aspect of JavaScript performance. In this case, we're comparing the performance of two approaches:

1. Window object access: Both test cases attempt to access the window object, which is a fundamental concept in JavaScript.
2. Variable assignment and usage: The second test case introduces variable assignment (var p = ...) and usage (p;).

Options compared

The two test cases differ in their approach to accessing and manipulating the window object:

1. Test 1: $(window): This approach uses a jQuery-like syntax ($(window)) to access the window object. This method is commonly used in browser environments, where jQuery or other libraries provide an easy way to manipulate the DOM.
2. Test 2: var p = window;: In this test case, a variable p is assigned the value of the window object using the var keyword. The subsequent lines (p; and p;) demonstrate simple variable usage.

Pros and cons of each approach

1. Test 1: $(window)
   • Pros:
     • Easy to read and write, especially in a jQuery-heavy environment.
     • May be faster due to optimized library functions.
   • Cons:
     • Requires the presence of jQuery or another library, which can add overhead.
     • Might not be suitable for environments without these libraries.
2. Test 2: var p = window;
   • Pros:
     • Lightweight and easy to understand.
     • No external dependencies required.
   • Cons:
     • May require more manual memory management, which can impact performance.
     • Less readable than the jQuery-like syntax.

Other considerations

When running these benchmarks, consider the following:

1. Browser environment: Both test cases are likely to behave similarly in most modern browsers, but differences may arise due to specific browser implementations or extensions.
2. Library dependencies: Test 1 relies on jQuery or a similar library, which can impact performance. Make sure to test with and without these libraries to isolate the effect of the $(window) syntax.
3. Variable usage patterns: The simple variable assignments (p;) in Test 2 might be more representative of real-world scenarios, where variables are frequently accessed and manipulated.

Library usage

In this benchmark, jQuery is used as a library to provide the $ function, which allows for easy access to the window object. Other libraries might have similar functionality or different syntaxes for accessing the global object.

Special JS features/syntax

None of the provided benchmarks involve special JavaScript features or syntax that require additional explanation.