Determine the category of a nested key within a different type

Question

Determine the category of a nested key within a different type

I'm currently utilizing graphql-codegen which generates types in the following structure:

type Price = {
  onetime: number;
  monthtly: number;
};

type CarModel = {
  price: Price;
  name: string;
};

type Car = {
  model: CarModel;
  someOtherAttribute: string;
};

type MyCarQuery = Pick<Car, "someOtherAttribute"> & {
  model: Pick<CarModel, "name"> & {
    price: Pick<Price, "onetime">;
  };
};

I am interested in isolating the type of

MyCarQuery -> model -> price

and using it independently. Essentially, I want to create a type definition for Pick<Price, "onetime"> without redundant definitions.

Is there a method to achieve this without duplicating the types?

typescript typescript-typings

Answer 1

Answer №1

Here is the solution you're searching for:

type TheType = MyCarQuery["model"]["price"];

Check it out in the playground.

This assignment defines TheType as {onetime: number}, but if you modify Price to have onetime as a string, then TheType will become {onetime: string}.

Unfortunately, there isn't an explicit reference in the Handbook for this concept, so I learned about it from various Stack Overflow responses.

Answer 2

Here is the solution you're searching for:

type TheType = MyCarQuery["model"]["price"];

Check it out in the playground.

This assignment defines TheType as {onetime: number}, but if you modify Price to have onetime as a string, then TheType will become {onetime: string}.

Unfortunately, there isn't an explicit reference in the Handbook for this concept, so I learned about it from various Stack Overflow responses.

Determine the category of a nested key within a different type

Answer №1

Similar questions

What is the method to assert that two arguments are equal within a function?

What sets apart extending and intersecting interfaces in TypeScript?

Listening for Angular 2 router events

Is there a way to dynamically exclude files from the TypeScript compiler?

The ASP.NET Core Web API successfully sends back a response, but unfortunately, the frontend is only seeing an empty value along with a status code of 200 (OK)

Currently, my goal is to create PDFs using Angular

Issue with data-* attributes in MaterialUI React component causing TypeScript error

Advanced automatic type inference for object literals in TypeScript

Having trouble running `npm start` on my NodeJs project

Typescript function incorrectly returns Protractor's "element.all" output as Promise<string> instead of Promise<string[]>

What is the connection between tsconfig.json and typings.json files?

Error message in Ionic 2: "Property is not found on type"

What is the best way to merge multiple nested angular flattening operators together?

Using createStackNavigator along with createBottomTabNavigator in React Navigation version 5

During the execution of Jest tests, a singular module is experiencing undefined imports

How can we create a unique type in Typescript for a callback that is void of any return value?

Customizing a generic method in typescript

Retrieving Data from Repeated Component in Angular 6

The ngxpagination template is currently experiencing issues with filtering and pagination functionality

Error message: "Mismatched data types in Formik errors when utilizing TypeScript"