Hey dognie, good you are interested in webApp development. But when coming to hybrid app development mostly ionic you have to deal with angular.js, a MVC framework created by awesome people at google. So you have to learn and good at angular if you want build apps using ionic.
Coming to your question directly for ionic 1 you have to know angular 1. > and for ionic 2 you have to good at angular 2 comprises of Typescript and ES6 which recently moved out of beta, and you can start from angular2 there is no dependency on angular 1.