In the context of web apps, animation is nothing more than the visualization of change over a specified duration. This visualization of change is very important because when done right we can use this to dramatically increase the user experience of an app and make our apps feel more refined and well designed.
At the highest level, the Web Animations API is a standardized JavaScript API which is baked into browsers that allows developers to animate DOM elements. CSS was always been the most performant way to animate on the web because the CSS animations engine can run animations on the GPU instead of the CPU allowing us to achieve smooth 60 fps animations. The Web Animations API finally allows us to write animation logic using JavaScript and opens up the browsers animation engine allowing us to run these animations on the GPU. As well as performant animations there are host of other benefits the Web Animations API provides us. Because it is a JavaScript API we can easily create dynamic animations by altering durations, easing methods and other variables; something which is very hard to do in CSS. The API provides very flexible playback control which allows us to Pause, Rewind, Skip and even change the rate of playback and more. The API is Promise based so it is really easy to chain multiple animations or run other logic when the animation completes. And because the Web Animations API is a browser feature there are no external dependencies to manage or maintain. Today most JavaScript libraries take a component based approach. Whether that’s using Angular, React, VueJS or just native web components the Web Animations API fits in with this architecture because the JavaScript used to create this animations can be embedded into the components easily without any dependencies. These are great benefits provided by the Web Animations API which we can use to harness the power of the GPU to create silky smooth animations that are dynamic and flexible.