Angular 2 is different from Angular 1 as it is written completely in Typescript and includes the ES6 specification. As it is not updated version of Angular 1.x so it is rewritten and has many changes.
Component based Programming:
Angular2 is component based programming language like ReactJs. Component create faster entities that are less dependent. We can say that controllers of angular1 are replaced with Components in Angular2. In Angular1 there is modular programming concept.