How expand typescript type?-CodePudding

I have a location that returns a Location that has an undefined state (unknown). I can't figure out how I can extend the Location interface type so that I don't get an error that form doesn't exist.

TS2571: Object is of type 'unknown'.

  const location: Location = useLocation();

  const fromPage: string = location.state?.form || ENDPOINTS.GET_LIST_REPORTS;

CodePudding user response：

You can use the generic type of useLocation().

interface LocationState {
  from: {
    pathname: string;
  };
}
const location = useLocation<LocationState>();

const { from } = location.state || { from: { pathname: "/" } };

Code from answer in this post. https://stackoverflow.com/a/61669105/4490246

CodePudding user response：

You can extend your Location with type

type ExtendedLocation = Location & { state?: { form: string } }

const location: ExtendedLocation = useLocation();

const fromPage: string = location.state?.form || ENDPOINTS.GET_LIST_REPORTS;

Or with an extended interface

interface ExtendedLocation extends Location {
  state?: { form: string }
}

const location: ExtendedLocation = useLocation();

const fromPage: string = location.state?.form || ENDPOINTS.GET_LIST_REPORTS;