How can I use type parameter T in next code block (typeOf, instanceOf,...). T is 'Group'. Is it possible because JavaScript does not have types. Thanx.
export class LocalStorage<T> implements ILocalStorage<T> {
constructor() {}
getKey(): string {
if (T is 'Group')
return "Groups";
}
}
You cannot do it for TypeArguments in generics (as you have already realized). But you can do runtime checking if you use TypeScript classes:
class Group{}
function getKey(item:any): string {
if (item instanceof Group)
return "Groups";
else
return 'invalid';
}
console.log(getKey(new Group()));
There is no typescript magic in the above code. We are simply utilizing the javascript instanceof operator : https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/instanceof
Thanx basarat. You point me to right direction. My code now looks better.
export class LocalStorage<T> implements ILocalStorage<T> {
private instance: any;
constructor(instance: any) {
this.instance = new instance(null);
}
getKey(): string {
if (this.instance instanceof g.Group)
return "Groups";
else
return "Invalid";
}
}
//using
var groupLocalStorage = new ls.LocalStorage<g.Group>(g.Group);