TypeScript set a type or interface to be any member of an enum

Issue

I wanted to know what was the best way to set a type value to any member of an enum.

example

enum daysOfWeekEnum{
    mon = 'Monday',
    tue = 'Tuesday',
    wed = 'Wednesday', 
    thu = 'Thursday',
    fri = 'Friday',
    sat = 'Saturday',
    sun = 'Sunday'
}
//any day of week
type dayOfWeek = daysOfWeekEnum

//effective assign the values in this way
type day = 'Monday' | 'Tuesday' | 'Wednesday' 

Solution

The enum is a type itself that can represent any value out of the set of declared values.

enum daysOfWeekEnum {
    mon = 'Monday',
    tue = 'Tuesday',
    wed = 'Wednesday', 
    thu = 'Thursday',
    fri = 'Friday',
    sat = 'Saturday',
    sun = 'Sunday'
}

let day: daysOfWeekEnum = daysOfWeekEnum.mon;

function log(value: daysOfWeekEnum) {
    console.log(value);
}

log(day); // ok -- prints "Monday"
log("Monday"); // ok -- prints "Monday"
log("asdfa"); // not ok - typescript error, "asdfa" is not a daysOfWeekEnum value

Answered By - Norman Breau