How to Convert an Enum to a Number in TypeScript

To convert an enum to a number in TypeScript, you can use type casting or explicit value assignment. Here are a few examples:

1. Type Casting:

enum Color {
   
  Red,
  Green,
  Blue,
}

const color: Color = Color.Red;
const colorNumber: number = color as number;
console.log(colorNumber); // Output: 0

In this example, we have an enum called Color with three members: Red, Green, and Blue. We assign the Color.Red member to the color variable. By using type casting (as number), we can convert the color enum member to a number. The colorNumber variable will have the value 0 when logged to the console.

2. Explicit Value Assignment:

enum Color {
   
  Red = 1,
  Green = 2,
  Blue = 3,
}

const color: Color = Color.Red;
const colorNumber: number = color;
console.log(colorNumber); // Output: 1

In this example, we assign explicit numeric values to the enum members. The Color.Red member is assigned the value 1. When we assign the color enum member to the colorNumber variable, TypeScript automatically assigns the corresponding numeric value. The colorNumber variable will have the value 1 when logged to the console.

Please note that when converting an enum to a number, the default behavior is to assign numeric values starting from 0 for the first enum member and incrementing by 1 for each subsequent member. However, you can explicitly assign custom numeric values to enum members as shown in the second example.