Functional style Immutable Store tests

oop-to-fp-immutable-store-tests.js

const initialState = {
  1: circle([2.5, 0], 1.5),
  2: circle([-2, 0], 2),
};
const { getState, dispatch } = createStore(initialState, reducer);

area(getState(1).r); // -> 7.0685834705770345;
area(getState(2).r); // -> 12.566370614359172;
const [hit] = intersect(getState(1), getState(2));
hit; // -> false
if (hit) dispatch({ type: 'hit', id1: 1, id2: 2 });
getState(1).hits; // -> 0

dispatch({ type: 'move', payload: [1, 0], id: 1 });
const [hit2] = intersect(getState(1), getState(2));
hit2; // -> true
if (hit2) dispatch({ type: 'hit', id1: 1, id2: 2 });
getState(1).hits; // -> 1
getState(2).hits; // -> 1

initialState[1].hits = 4; // -> THROWS!
getState(1).hits = 4; // -> THROWS!
getState(1).hits; // -> 1