DEV Community

Cover image for typeof and lookup type in typescript
Rubin
Rubin

Posted on

typeof and lookup type in typescript

#typescript #types #javascript
  • The typeof key can be used to extract type from an existing data 
const user = { name: "Rubin", age: 15, address: "Kathmandu" } type UserType = typeof user // {name: string,age:number,address: string}
Enter fullscreen mode Exit fullscreen mode
  • Look up types on the other hand are used to extract a portion from a complex type and create a new type 
type requestType = { payload: { name: string, user: number, roles: { edit: boolean, create: boolean, read: boolean } }, params: { id: number, type: string } } // if we want to use type of params as a type then type Params = requestType["params"] // {id: number,type: string } type Roles = requestType["payload"]["roles"] // roles: {edit: boolean,create: boolean,read: boolean}
Enter fullscreen mode Exit fullscreen mode

Top comments (0)