Check if string exist in const typescript

Question

I have some const like this

export class CustomerType {
  static readonly main = 'mainCustomer';
  static readonly additional = 'additionalCustomer';
}

And I have

const value = 'main'

Is it possible to check does value exist in CustomerType and return true or false? I know that I can use include when is an array but this is class?

Answer 1

You can use Object.keys() to get all properties on the class and then use Array.prototype.includes() to see if it is contained:

class CustomerType {
  static readonly main = 'mainCustomer';
  static readonly additional = 'additionalCustomer';
}

const value = 'main'


console.log(Object.keys(CustomerType).includes(value))

You can see this working in the typescript playground .

Answer 2

type valueType = keyof typeof CustomerType

const value: valueType = 'main'; // no error

const value2: valueType = 'something else'; // throws typescript error

See an example in the typescript playground here .