useDLE()

Type

function useDLE(
  endpoint: ReadEndpoint,
  ...args: Parameters<typeof endpoint> | [null]
): {
  data: Denormalize<typeof endpoint.schema>;
  loading: boolean;
  error: Error | undefined;
};

With Generics

function useDLE<
  E extends EndpointInterface<FetchFunction, Schema | undefined, undefined>,
  Args extends readonly [...Parameters<E>] | readonly [null],
>(
  endpoint: E,
  ...args: Args
): {
  data: DenormalizeNullable<typeof endpoint.schema>;
  loading: boolean;
  error: Error | undefined;
};

In case you cannot use suspense, useDLE() is just like useSuspense() but returns [D]ata [L]oading [E]rror values.

Hook usage

Fixtures

GET /profiles

[{"id":"1","fullName":"Einstein","bio":"Smart physicist"},{"id":"2","fullName":"Elon Musk","bio":"CEO of Tesla, SpaceX and owner of Twitter"}]

▶api/Profile.ts

import { Entity, createResource } from '@rest-hooks/rest';

export class Profile extends Entity {
  readonly id: number | undefined = undefined;
  readonly img: string = '';
  readonly fullName: string = '';
  readonly bio: string = '';

  pk() {
    return this.id?.toString();
  }
}

export const ProfileResource = createResource({
  path: '/profiles/:id',
  schema: Profile,
});

▶ProfileList.tsx

import { useDLE } from 'rest-hooks';
import { ProfileResource } from './api/Profile';

function ProfileList(): JSX.Element {
  const { data, loading, error } = useDLE(ProfileResource.getList);
  if (error) return <div>Error {error.status}</div>;
  if (loading || !data) return <>loading...</>;
  return (
    <div>
      {data.map(profile => (
        <div key={profile.pk()}>
          <h4>{profile.fullName}</h4>
          <p>{profile.bio}</p>
        </div>
      ))}
    </div>
  );
}
render(<ProfileList />);

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Conditional Dependencies

Use null as the second argument on any rest hooks to indicate "do nothing."

// todo could be undefined if id is undefined
const todo = useDLE(getTodo, id ? { id } : null);