enum-mixed-keys.ts

/**
* Get all keys from enumeration.
*/
public static keys(enumType: object) {
  const members = Object.keys(enumType);<br /> let keys: string[];
  if (!EnumHelpers.isNumeral(enumType)) {
    keys = members;
  } else {
    keys = [];
    members.forEach(x => {
      const parsedValue = parseInt(x, 10);
      if (Number.isNaN(parsedValue)) {
        keys.push(x);
      }
    });
  }
  // key of enumeration can't be number 
  return keys.filter(x => Number.isNaN(parseInt(x, 10)));
}