redux-selector-composition.js

const bindSelectors = (selectors, stateSlice) =>
  Object.keys(selectors).reduce((prev, curr) =>
    ({ ...prev, [curr]: (...args) => {
      const [state, ...rest] = args;
      return selectors[curr](state[stateSlice], ...rest);
    }}),
    {}
  );

// State

const _state = {
  value: 'A',
  b: {
    value: 'B',
    c: {
      value1: 7,
      value2: 12,
    },
  },
};

// File C (Very deep)

const fromC = {
  getC1: state => state.value1,
  getC2: state => state.value2,
};

// File B (Has access to C and itself)
const inheritedFromC = bindSelectors(fromC, 'c');

const fromB = {
  ...inheritedFromC,
  getAllC: state => inheritedFromC.getC1(state) + inheritedFromC.getC2(state),
  getB: (state, extra) => state.value + extra,
};

// File A
const inheritedFromB = bindSelectors(fromB, 'b');

const fromA = {
  ...inheritedFromB,
  getA: state => state.value,
};

// RESULT (state tree is no concern anymore)

fromA.getA(_state); //  "A"
fromA.getB(_state, ' foo'); // "B foo"
fromA.getAllC(_state); // 19
fromA.getC1(_state); // 7