Question/Idea about form state dirty values about ngrx-forms HOT 7 CLOSED

import {
  AbstractControlState,
  FormArrayState,
  FormControlState,
  FormControlValueTypes,
  FormGroupState,
  isGroupState,
  isArrayState,
  KeyValue,
} from 'ngrx-forms';

export function getFilteredValue<T extends FormControlValueTypes>(
  state: FormControlState<T>,
  filterFn: (state: AbstractControlState<T>) => boolean,
): T | undefined;

export function getFilteredValue<T>(
  state: FormArrayState<T>,
  filterFn: (state: AbstractControlState<any>) => boolean,
): T[] | undefined;

export function getFilteredValue<T extends KeyValue>(
  state: FormGroupState<T>,
  filterFn: (state: AbstractControlState<any>) => boolean,
): Partial<T> | undefined;

export function getFilteredValue<T>(
  state: AbstractControlState<T>,
  filterFn: (state: AbstractControlState<any>) => boolean,
): T | undefined;

export function getFilteredValue<T>(
  state: AbstractControlState<T>,
  filterFn: (state: AbstractControlState<T>) => boolean,
): T | Partial<T> | T[] | undefined {
  if (!filterFn(state)) {
    return undefined;
  }

  if (isGroupState(state)) {
    const groupState = state;
    return Object.keys(groupState.controls).reduce((c, key) => {
      const childState = groupState.controls[key];
      const filteredValue = getFilteredValue(childState, filterFn);

      if (filteredValue !== undefined) {
        Object.assign(c, { [key]: filteredValue });
      }

      return c;
    }, {} as Partial<T>);
  }

  if (isArrayState(state)) {
    return state.controls.map(childState => getFilteredValue(childState, filterFn)!).filter(s => !!s);
  }

  return state.value;
}