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How can I loop through enum values for display in radio buttons?

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enumhowdisplayradioforbuttonscanvaluesloopthrough

Problem

What is the proper way to loop through literals of an enum in TypeScript?

(I am currently using TypeScript 1.8.1.)

I've got the following enum:

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);
        }
    }


The result displayed is a list

0
1
2
3
Intrusion,
Identification,
AbsenceTest,
Autre


I do want only four iterations in the loop as there are only four elements in the enum. I don't want to have 0 1 2 and 3 that seem to be index numbers of the enum.

Solution

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)

Edit

String enums look different than regular ones, for example:

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 just gives you this object:

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


You can get all the keys (["A", "B", "C"]) like this:

Object.keys(MyEnum);


And the values (["a", "b", "c"]):

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


Or using Object.values():

Object.values(MyEnum)

Code Snippets

for (let item in MotifIntervention) {
    if (isNaN(Number(item))) {
        console.log(item);
    }
}
Object.keys(MotifIntervention).filter(key => !isNaN(Number(MotifIntervention[key])));
enum MyEnum {
    A = "a",
    B = "b",
    C = "c"
}
var MyEnum;
(function (MyEnum) {
    MyEnum["A"] = "a";
    MyEnum["B"] = "b";
    MyEnum["C"] = "c";
})(MyEnum || (MyEnum = {}));
{
    A: "a",
    B: "b",
    C: "c"
}

Context

Stack Overflow Q#39372804, score: 707

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