this is a different statement than the sentence i responded to. square or round just indicates the direction of the binding. everything in angular is also vanilla js.
In React, there is no 'direction' of binding---its all one way, just like in vanilla Javascript, and in fact no binding on anything except low level elements' like divs. Components only receive props, which do not do anything at all until you write code that reads them and runs operations based on their values.
Thus components are simply function calls (it's what they compile to anyways), and JSX is just a syntax to write functional code.