Object Oriented Example

oop-and-fp_oop.ts

class Customer {
	firstname: string
	middlename: string
	lastname: string
    age: number

	formattedName: string
	
	isLegalAge () {
		return this.age >= 18;
	}

	getStatus (): string {
		return 'Status: ' + this.isLegalAge() ? 'Allowed' : 'Not Allowed'
    }

	formatCustomerName (formatter: ICustomerFormatter) {
        this.formattedName = 'Name: ' + formatter.format(this);
    }

}

interface ICustomerFormatter {

	format(customer: Customer): string
}

class SalesClerkCustomerFormatter implements ICustomerFormatter {

	format(customer: Customer): string {
		let formattedName = `${customer.lastname}, ${customer.firstname}`;
		if (customer.middlename) {
			if (customer.middlename[0]) {
				return formattedName = `${formattedName} ${customer.middlename[0]}.`
			}
		}
		return 'Name: ' + formattedName;
	}
}

class ReportingCustomerFormatter implements ICustomerFormatter {

	format(customer: Customer): string {

		throw new Error('not implemented yet');
	}
}


let customer = new Customer();
customer.firstname = 'sansa';
customer.middlename = 'tully';
customer.lastname = 'stark';

customer.formatCustomerName(new SalesClerkCustomerFormatter());
customer.formatCustomerName(new ReportingCustomerFormatter());

customer.formattedName; // formatted customer name;