[Edit]

TypeScript - enum type

1 contributors

2 contributions

0 discussions

5 points

Created by:

Bess

571

In TypeScript it is possible to create enum type in following ways.

1. Automatic numeric `enum` members example

Edit

xxxxxxxxxx
 
enum Color
{
    Red,   // 0
    Green, // 1
    Blue   // 2
}
​
let blue : Color = Color.Blue;
​
console.log(Color.Red);
console.log(Color.Green);
console.log(blue);

Output:

xxxxxxxxxx
 
0
1
2

2. Computed and constant `enum` members example

Edit

xxxxxxxxxx
 
enum Mode
{
    Read = 1 << 1,
    Write = 1 << 2,
    Both = Read | Write
}
​
let read : Mode = Mode.Read;
​
console.log(read);
console.log(Mode.Write);
console.log(Mode.Both);

Output:

xxxxxxxxxx
 
2
4
6

3. Assigned numeric `enum` members example - auto counting

Edit

xxxxxxxxxx
 
enum Value
{
    Two = 2,
    Three, // 3
    Four,  // 4
    Six = 6,
    Seven  // 7
}
​
let two : Value = Value.Two;
​
console.log(two);
console.log(Value.Three);
console.log(Value.Seven);

Output:

xxxxxxxxxx
 
2
3
7

4. String `enum` members example

Edit

xxxxxxxxxx
 
enum Pet {
    Dog = 'Dog',
    Cat = 'Cat',
    Rabbit = 'Rabbit'
}
​
let dog : Pet = Pet.Dog;
​
console.log(dog);
console.log(Pet.Cat);
console.log(Pet.Rabbit);

Output:

xxxxxxxxxx
 
Dog
Cat
Rabbit

5. Generating logic `enum` members example

Edit

xxxxxxxxxx
 
let counter = 0;
​
enum Key {
    A = counter *= 2,
    B = counter *= 2,
    C = counter *= 2
}
​
let a : Key = Key.A;
​
console.log(a);
console.log(Key.B);
console.log(Key.C);

Output:

xxxxxxxxxx
 
1
2
3

6. Heterogeneous `enum` members example - strings + numbers

Edit

xxxxxxxxxx
 
enum Mix {
    Drink = 1,
    Food = 2,
​
    Sweet = '1/3',
    Normal = '2/3',
    Sour = '3/3'
}
​
let drink : Mix = Mix.Drink;
​
console.log(drink);
console.log(Mix.Sweet);
console.log(Mix.Sour);