we need to understand how Vue's transition component works, then we'll build our first simple transition animation. Vue Transitions. Before we begin,Vue's transition system offers many simple ways to animate entering, leaving, and lists, but what about animating your data itself . Vue.js is an open-source model–view–viewmodel front end JavaScript framework for building user interfaces and single-page applications. It was created by Evan You, and is maintained by him and the rest of the active core team members.