git.r.bdr.sh - rbdr/forum/blob - src/lib/stores/apollo.ts

   1 import { ApolloError } from '@apollo/client/core';
   2 import { readable } from 'svelte/store';
   3 import { client } from '$lib/config/apollo';
   4 import type { DocumentNode, ApolloQueryResult } from '@apollo/client/core';
   5
   6 import type { Readable } from 'svelte/store';
   7
   8 /*
   9  * This is a generic store for use with apollo
  10  */
  11
  12 type ApolloStoreConfiguration<Type> = {
  13   key: string,
  14   query: DocumentNode,
  15   initialValue?: Type | void
  16   variables?: object
  17 };
  18
  19 type ApolloStoreState<Type> = {
  20   loading: boolean,
  21   data: Type | void,
  22   error: Error | void
  23 };
  24
  25 export const store = function store<Type>({ key, query, initialValue = null, variables = {} }: ApolloStoreConfiguration<Type>): Readable<ApolloStoreState<Type>> {
  26
  27   const initialState: ApolloStoreState<Type> = {
  28       loading: true,
  29       data: initialValue,
  30       error: undefined
  31   };
  32
  33   return readable(
  34     initialState,
  35     (set) => {
  36
  37       const handleError = function (error: Error) {
  38
  39         return set({
  40           loading: false,
  41           data: initialValue,
  42           error
  43         });
  44       };
  45
  46       client.watchQuery({ query, variables }).subscribe(
  47         (result: ApolloQueryResult<Type>) => {
  48
  49           if (result.errors) {
  50             const error = new ApolloError({ graphQLErrors: result.errors });
  51             return handleError(error);
  52           }
  53
  54           set({
  55             loading: false,
  56             data: result.data[key],
  57             error: undefined
  58           });
  59         },
  60         (error: Error) => handleError(error)
  61       );
  62     }
  63   );
  64 };