ResizeObserver, Mutation Observer, and Intersection Observers are more performant APIs than their older counterparts.
To use an observer, create a new observer, do something with the observed changes via the observer function, observe a specific element, and optionally unobserve the element.
Improvements can be made to the observer APIs like simplifying the way ResizeObserver code is written.
Refactoring ResizeObserver code can involve encapsulating the observer creation and passing elements as parameters.
Passing a callback function into resizeObserver can make it operate like an event listener for element resize events.
ResizeObserver's observe method can take in an options object to determine what changes to observe.
An optional event listener pattern can be implemented for ResizeObserver by emitting a custom event.
Providing methods to unobserve and disconnect from observing elements adds flexibility to the observer usage.
The article discusses an enhanced version of ResizeObserver by Splendid Labz and its features for observing multiple elements.
The refactoring exercise aims to make code easier to use and maintain, emphasizing the importance of refactoring for improved code quality.