1 files changed, 62 insertions, 0 deletions
diff --git a/src/lib/stores/apollo.ts b/src/lib/stores/apollo.ts
new file mode 100644
index 0000000..4ef1986
--- /dev/null
+++ b/src/lib/stores/apollo.ts
@@ -0,0 +1,62 @@
+import { ApolloError } from '@apollo/client/core';
+import { readable } from 'svelte/store';
+import { client } from '$lib/config/apollo';
+import type { DocumentNode, ApolloQueryResult } from '@apollo/client/core';
+
+import type { Readable } from 'svelte/store';
+
+/*
+ * This is a generic store for use with apollo
+ */
+
+type ApolloStoreConfiguration<Type> = {
+	key: string;
+	query: DocumentNode;
+	initialValue?: Type | void;
+	variables?: object;
+};
+
+type ApolloStoreState<Type> = {
+	loading: boolean;
+	data: Type | void;
+	error: Error | void;
+};
+
+export const store = function store<Type>({
+	key,
+	query,
+	initialValue = null,
+	variables = {}
+}: ApolloStoreConfiguration<Type>): Readable<ApolloStoreState<Type>> {
+	const initialState: ApolloStoreState<Type> = {
+		loading: true,
+		data: initialValue,
+		error: undefined
+	};
+
+	return readable(initialState, (set) => {
+		const handleError = function (error: Error) {
+			return set({
+				loading: false,
+				data: initialValue,
+				error
+			});
+		};
+
+		client.watchQuery({ query, variables }).subscribe(
+			(result: ApolloQueryResult<Type>) => {
+				if (result.errors) {
+					const error = new ApolloError({ graphQLErrors: result.errors });
+					return handleError(error);
+				}
+
+				set({
+					loading: false,
+					data: result.data[key],
+					error: undefined
+				});
+			},
+			(error: Error) => handleError(error)
+		);
+	});
+};