You need to change the prototype:
interface Date {
ConvertToDateFromTS(msg: string): Date;
}
Date.prototype.ConvertToDateFromTS = function(msg: string): Date {
// implement logic
}
let oldDate = new Date();
let newDate = oldDate.ConvertToDateFromTS(TS_VALUE);
Though it looks like you want to have a static factory method on the Date
object, in which case you better do something like:
interface DateConstructor {
ConvertToDateFromTS(msg: string): Date;
}
Date.ConvertToDateFromTS = function(msg: string): Date {
// implement logic
}
let newDate = Date.ConvertToDateFromTS(TS_VALUE);