Parse an object recursively, applying a test function to each entry and return true on the first entry which passes the test function.

filterDeep.ts

/**
 * This method will scan the provided object recursively looking for entries which match the test function. When one is found will return true. Sample Usage:
 * ```
 * // Return those objects in the objArray with an entry equal to apple.
 * objArr.filter(x, (o, k) => o[k] === 'apple');
 * ```
 * 
 * @param o The object to filter.
 * @param fn The predicate function to test at each level of the object.
 * @returns A boolean which when true indicates that the object meets the condition.
 */
export function filterDeep<T extends object>(o: T, fn: (obj: T[keyof T], key: keyof T) => boolean): boolean {
  for (const i in o) {
    if (fn.apply(this, [o, i, o[i]])) {
      return true;
    } 
    if (o[i] !== null && typeof(o[i]) === 'object') {
      filterObject(<any>o[i], fn); // If anyone feels like tackling this one let me know...
    }
  }
  return false;
}