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Enums

Enums (enumerations) allow you to define a set of named constants. Using enums can make it easier to document intent, or create a set of distinct cases.

Defining an Enum​

You can define an enum using the enum keyword.

enum Color {
    Red,
    Green,
    Blue,
}

By default, the values of an enum start from 0 and increment by 1 for each member.

Explicit Values​

You can also explicitly set the value of an enum member.

enum Status {
    Pending = 0,
    InProgress = 5,
    Completed = 10,
    Failed = -1,
}

If a member doesn't have an explicit value, it will increment from the previous member's value.

Using Enums​

You can access enum members using the dot notation.

let red: Color = Color.Red;
let status: Status = Status.InProgress;

if (status == Status.Completed) {
    print "Task completed!";
}

Enum as Types​

Enums can be used as types for variables, function parameters, and return values.

function getColorName(color: Color): string {
    if (color == Color.Red) return "Red";
    if (color == Color.Green) return "Green";
    if (color == Color.Blue) return "Blue";
    return "Unknown";
}