TypeScript enum to object array

Question

I have an enum defined this way:

export enum GoalProgressMeasurements {
    Percentage = 1,
    Numeric_Target = 2,
    Completed_Tasks = 3,
    Average_Mile         


        

Answer 1

I didn't like any of the above answers because none of them correctly handle the mixture of strings/numbers that can be values in TypeScript enums.

The following function follows the semantics of TypeScript enums to give a proper Map of keys to values. From there, getting an array of objects or just the keys or just the values is trivial.

/**
 * Converts the given enum to a map of the keys to the values.
 * @param enumeration The enum to convert to a map.
 */
function enumToMap(enumeration: any): Map {
  const map = new Map();
  for (let key in enumeration) {
      //TypeScript does not allow enum keys to be numeric
      if (!isNaN(Number(key))) continue;

      const val = enumeration[key] as string | number;

      //TypeScript does not allow enum value to be null or undefined
      if (val !== undefined && val !== null)
          map.set(key, val);
  }

  return map;
}

Example Usage:

enum Dog {
    Rover = 1,
    Lassie = "Collie",
    Fido = 3,
    Cody = "Mutt",
}

let map = enumToMap(Dog); //Map of keys to values

lets objs = Array.from(map.entries()).map(m => ({id: m[1], name: m[0]})); //Objects as asked for in OP
let entries = Array.from(map.entries()); //Array of each entry
let keys = Array.from(map.keys()); //An array of keys
let values = Array.from(map.values()); //An array of values

I'll also point out that the OP is thinking of enums backwards. The "key" in the enum is technically on the left hand side and the value is on the right hand side. TypeScript allows you to repeat the values on the RHS as much as you'd like.