Dynamic reselect selector

dynamicSelector.js

export function createDynamicSelector() {
  let subSelectors = null;
  let actualSelector = null;

  return (state, props, ...args) => {
    // Check to see if the sub state has change
    const subState = state.get('subState');
    if (subSelectors === null || !Set(subState.keys()).equals(Set(subSelectors.keys()))) {
      // Rebuild our the selectors - could obviously update if required.
      subSelectors = subState.map((value, key) => {
        return createSubSelector(
          (state) => state.getIn(['subState', key])
        )
      });

      actualSelector = createSelector(
        ...subSelectors.toArray(),
        (...results) => {
          // Merge / convert as required
          return results;
        }
      )
    }

    return actualSelector(state, props, ...args);
  };
}


export function createSubSelector(subSelector) {
  return createSelector(
    subSelector,
    // Other selectors can still be in here!
    (subSubState) => {
      // Do stuff
      return subSubState
    }
  )
}