whitelizard

const func = (
  {
    fallbackMessage: msg = 'Unknown',
    offset = 4,
    pos: { x = 0, y = 0 } = {},
    ...options
  } = {},
  data = {},
) => {
  const { title = '', items: [head, ...tail] = [] } = data;

whitelizard

const func = (params = {}, data = {}) => {
  const {
    fallbackMessage: msg = 'Unknown',
    offset = 4,
    pos = {},
    ...options
  } = params;

  const { x = 0, y = 0 } = pos;
  const { title = '', items = [] } = data;

whitelizard

Circle.prototype.area.bind({ r: 4 })()

whitelizard

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

whitelizard

const reducer = (state, action) => {
  const actions = {
    move: ({ id, payload }) => ({ ...state, [id]: setPos(state[id], payload) }),
    hit: ({ id1, id2 }) => ({
      ...state,
      [id1]: incHits(state[id1]),
      [id2]: incHits(state[id2]),
    }),
  };
  return actions[action.type](action);

whitelizard

const deepFreeze = item => {
  const complex = Object(item) === item;
  if (Object.isFrozen(item) || !complex) return item;
  Object.values(item).forEach(deepFreeze);
  return Object.freeze(item);
};

const createStore = (initState = {}, reducer) => {
  let state = deepFreeze(initState);
  return {

whitelizard

const makeCircle = (pos = [0, 0], r = 0) => {
  let state = circle(pos, r);
  return {
    getState: () => state,
    incHits: () => (state = incHits(state)),
    setPos: pos => (state = setPos(state, pos)),
    area: () => area(r),
    intersect: c2 => {
      let hit;
      [hit, state] = intersect(state, c2.getState());

whitelizard

let c1 = circle([2.5, 0], 1.5);
let c2 = circle([-2, 0], 2);
const c2ref = c2; // Use a reference to c2 at this point in time

area(c1.r); // -> 7.0685834705770345
area(c2.r); // -> 12.566370614359172

let hit;
[hit, c1, c2] = intersect(c1, c2);
hit; // -> false

whitelizard

// Circle data object creator
const circle = (pos = [0, 0], r = 0) => ({ pos, r, hits: 0 });

// Immutable-updates helpers
const incHits = obj => ({ ...obj, hits: (obj.hits || 0) + 1 });
const setPos = (obj, pos = [0, 0]) => ({ ...obj, pos });

// Circle computations
const area = r => r ** 2 * Math.PI;

whitelizard

const c1 = makeCircle([2.5, 0], 1.5);
const c2 = makeCircle([-2, 0], 2);

c1.area(); // -> 7.0685834705770345
c2.area(); // -> 12.566370614359172

c1.intersect(c2); // -> false
c1.getHits(); // -> 0

c1.pos[0] = 1;