How can I iterate over enum values in order to display them as radio buttons? [duplicate]

Problem

In TypeScript, how do you loop through the literals of an enum?

(I’m using TypeScript 1.8.1 right now.)

The following enum is what I have:

export enum MotifIntervention {
    Intrusion,
    Identification,
    AbsenceTest,
    Autre
}

export class InterventionDetails implements OnInit
{
    constructor(private interService: InterventionService)
    {
        let i:number = 0;
        for (let motif in MotifIntervention) {
            console.log(motif);
        }
    }

A list is displayed as a result.

0
1
2
3
Intrusion,
Identification,
AbsenceTest,
Autre

Because there are only four members in the enum, I only want four iterations in the loop. I don’t want 0 1, 2, or 3 to appear as the enum’s index numbers.

Asked by Anthony Brenelière

Solution #1

Two options:

for (let item in MotifIntervention) {
    if (isNaN(Number(item))) {
        console.log(item);
    }
}

Or

Object.keys(MotifIntervention).filter(key => !isNaN(Number(MotifIntervention[key])));

(code in playground)

String enums, for example, differ from normal enums in appearance:

enum MyEnum {
    A = "a",
    B = "b",
    C = "c"
}

Compiles into:

var MyEnum;
(function (MyEnum) {
    MyEnum["A"] = "a";
    MyEnum["B"] = "b";
    MyEnum["C"] = "c";
})(MyEnum || (MyEnum = {}));

Which simply gives you the following object:

{
    A: "a",
    B: "b",
    C: "c"
}

All the keys ([“A”, “B”, “C”]) can be obtained in the following manner:

Object.keys(MyEnum);

The values ([“a”, “b”, “c”]) are as follows:

Object.keys(MyEnum).map(key => MyEnum[key])

Or using Object.values():

Object.values(MyEnum)

Answered by Nitzan Tomer

Post is based on https://stackoverflow.com/questions/39372804/how-can-i-loop-through-enum-values-for-display-in-radio-buttons