initial commit

packages/woocommerce-blocks/assets/js/data/collections/resolvers.js

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+/**
+ * External dependencies
+ */
+import { select, dispatch } from '@wordpress/data-controls';
+import { addQueryArgs } from '@wordpress/url';
+
+/**
+ * Internal dependencies
+ */
+import { receiveCollection, receiveCollectionError } from './actions';
+import { STORE_KEY as SCHEMA_STORE_KEY } from '../schema/constants';
+import { STORE_KEY, DEFAULT_EMPTY_ARRAY } from './constants';
+import { apiFetchWithHeaders } from '../shared-controls';
+
+/**
+ * Check if the store needs invalidating due to a change in last modified headers.
+ *
+ * @param {number} timestamp Last update timestamp.
+ */
+function* invalidateModifiedCollection( timestamp ) {
+	const lastModified = yield select( STORE_KEY, 'getCollectionLastModified' );
+
+	if ( ! lastModified ) {
+		yield dispatch( STORE_KEY, 'receiveLastModified', timestamp );
+	} else if ( timestamp > lastModified ) {
+		yield dispatch( STORE_KEY, 'invalidateResolutionForStore' );
+		yield dispatch( STORE_KEY, 'receiveLastModified', timestamp );
+	}
+}
+
+/**
+ * Resolver for retrieving a collection via a api route.
+ *
+ * @param {string} namespace
+ * @param {string} resourceName
+ * @param {Object} query
+ * @param {Array}  ids
+ */
+export function* getCollection( namespace, resourceName, query, ids ) {
+	const route = yield select(
+		SCHEMA_STORE_KEY,
+		'getRoute',
+		namespace,
+		resourceName,
+		ids
+	);
+	const queryString = addQueryArgs( '', query );
+	if ( ! route ) {
+		yield receiveCollection( namespace, resourceName, queryString, ids );
+		return;
+	}
+
+	try {
+		const {
+			response = DEFAULT_EMPTY_ARRAY,
+			headers,
+		} = yield apiFetchWithHeaders( { path: route + queryString } );
+
+		if ( headers && headers.get && headers.has( 'last-modified' ) ) {
+			// Do any invalidation before the collection is received to prevent
+			// this query running again.
+			yield invalidateModifiedCollection(
+				parseInt( headers.get( 'last-modified' ), 10 )
+			);
+		}
+
+		yield receiveCollection( namespace, resourceName, queryString, ids, {
+			items: response,
+			headers,
+		} );
+	} catch ( error ) {
+		yield receiveCollectionError(
+			namespace,
+			resourceName,
+			queryString,
+			ids,
+			error
+		);
+	}
+}
+
+/**
+ * Resolver for retrieving a specific collection header for the given arguments
+ *
+ * Note: This triggers the `getCollection` resolver if it hasn't been resolved
+ * yet.
+ *
+ * @param {string} header
+ * @param {string} namespace
+ * @param {string} resourceName
+ * @param {Object} query
+ * @param {Array}  ids
+ */
+export function* getCollectionHeader(
+	header,
+	namespace,
+	resourceName,
+	query,
+	ids
+) {
+	// feed the correct number of args in for the select so we don't resolve
+	// unnecessarily. Any undefined args will be excluded. This is important
+	// because resolver resolution is cached by both number and value of args.
+	const args = [ namespace, resourceName, query, ids ].filter(
+		( arg ) => typeof arg !== 'undefined'
+	);
+	//we call this simply to do any resolution of the collection if necessary.
+	yield select( STORE_KEY, 'getCollection', ...args );
+}