custom types in typescript
// simple type type Websites = 'www.google.com' | 'reddit.com'; let mySite: Websites = 'www.google.com' //pass //or let mySite: Website = 'www.yahoo.com' //error // the above line will show error because Website type will only accept 2 strings either 'www.google.com' or 'reddit.com'. // another example. type Details = { id: number, name: string, age: number }; let student: Details = { id: 803, name: 'Max', age: 13 }; // pass //or let student: Details = { id: 803, name: 'Max', age: 13, address: 'Delhi' } // error // the above line will show error because 'address' property is not assignable for Details type variables. //or let student: Details = { id: 803, name: 'Max', age: '13' }; // error // the above line will show error because string value can't be assign to the age value, only numbers.
