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.
This question is related to
javascript
arrays
typescript
enums
element
Two options:
for (let item in MotifIntervention) {
if (isNaN(Number(item))) {
console.log(item);
}
}
Or
Object.keys(MotifIntervention).filter(key => !isNaN(Number(MotifIntervention[key])));
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)
Source: Stackoverflow.com