In this particular code snippet, the variable types is not representing a data type but rather a constant value. Therefore, an alternative approach needs to be implemented.
One potential solution is to utilize an enumeration:
enum InputType {
Text = 1,
Password = 2
}
let inputType: InputType = InputType.Text;
However, it's worth noting that enumerations basically function as named numbers and lack compiler-enforced safety.
For instance, TypeScript would not flag errors when dealing with illogical assignments like the following:
let inputType: InputType = InputType.Text;
inputType = InputType.Password;
inputType = 72;
inputType = Math.PI;
To establish strict restrictions on available values, a specialized class can be created:
class InputType {
private static Instances = {
Text: new InputType("text"),
Password: new InputType("password")
};
private constructor(private _name:string) {
}
get Name() : string {
return this._name;
}
static get Password() : InputType{
return InputType.Instances.Password;
}
static get Text(): InputType{
return InputType.Instances.Text;
}
}
As the constructor is private, instances of this class cannot be directly created in other parts of the codebase. Instead, predefined values must be accessed through static getter methods.
Implementing this within the specified interface:
interface IAbstractFormElement {
value: string;
type: InputType;
required?: boolean;
disabled?: boolean;
}
var nameControl = <IAbstractFormElement>{
value: 'Harold',
type: InputType.Text
};
var passwordControl = <IAbstractFormElement>{
value: 'P@ssw0rd',
type: InputType.Password
}