remove unused parameters and improve code quality

[ltlylfun]

I noticed that the usage of some parameters didn't seem to follow conventions, so I modified them.

[ltlylfun]

The original code incorrectly included a third parameter in the Promise constructor:

return new Promise((resolve, reject, link) => { ... });

However, according to the JavaScript specification, the Promise executor function must only take two parameters: resolve and reject. Any additional parameters are ignored.

I refactored the code to define variables like link and request inside the executor function using const, which is the correct and idiomatic way to declare them:

return new Promise((resolve, reject) => {
  const link = document.createElement('link');
  ...
});

This makes the code cleaner, conforms to JavaScript best practices, and prevents potential bugs or confusion.

[ltlylfun]

In the original code:

function hasPrefetch(link) {
  link = document.createElement('link');
}

The link parameter was unused and immediately overwritten, which made it redundant and potentially misleading.
I removed the parameter and defined link as a const inside the function:

function hasPrefetch() {
  const link = document.createElement('link');
}

This makes the function cleaner, easier to read, and avoids confusion about the purpose of the parameter. It also follows best practices by minimizing the function's input to only what is necessary.