Add ability to style button hover

[ArbiterOfBuffoonery]

This change stems from the flex-toolbar issue discussion.

[ArbiterOfBuffoonery]

The build check warning about adding a function inside a loop has made me realize that if there is more than one property they will not all be applied since the onmouseenter and onmouseleave functions would just point to the last property...I'm going to close this and think about it some more as I need to iterate all the properties in the function instead of how I am doing it now, but I'm not quite sure how that should work at the moment.

[UziTech]

You would also have a problem that button and propName are changed by a for loop so they will always be the last value in the array inside the anonymous functions.

https://stackoverflow.com/a/13977142/806777

I would try creating a function that take the btn and return a function for the listeners.

something like:

if (btn.hover && !disable) {
  button.element.addEventListener('mouseenter', this.onMouseEnter(btn), {passive: true});

...

onMouseEnter(btn) {
  return function () {
    for (const propName in btn.hover) {
      const style = btn.hover[propName];
      this.style[changeCase.camelCase(propName)] = style;
    }
  };
},

[UziTech]

Make sure to use tabs and align the for loop in onMouseEnter

[UziTech]

Could you save the changeCase.camelCase(propName) to a variable instead of calculating it every time it is needed?

Also if you change the propName in btn.preHoverVal[propName] to the camel case variable you won't need to calculate the camel case prop name in onMouseLeave

[ArbiterOfBuffoonery]

Sorry about the formatting issue, I should have caught that...

Also, I should have caught the camel case conversion. I even thought about this briefly, but instead of reading up on what it was actually doing, I (incorrectly) assumed it was something that was "needed" and dismissed it without further thought. The name even implies it is a string manipulation function that would be more efficient to run once 😞.

[UziTech]

No problem. I will merge this and create a new release tonight. Thanks a lot for this, it is incredibly useful. 💯

[ArbiterOfBuffoonery]

Happy to help! Thanks for providing guidance and feedback, it was good information to learn.

[UziTech]

released in v2.1.0 Thanks again