move fetch-link-suggestions to a separate file and refactor it

packages/edit-navigation/src/index.js

@@ -1,8 +1,7 @@
 /**
  * External dependencies
  */
-import { map, set, flatten, partialRight } from 'lodash';
-
+import { set } from 'lodash';
 /**
  * WordPress dependencies
  */
@@ -12,17 +11,14 @@ import {
 } from '@wordpress/block-library';
 import { render } from '@wordpress/element';
 import { createHigherOrderComponent } from '@wordpress/compose';
-import { __ } from '@wordpress/i18n';
-import apiFetch from '@wordpress/api-fetch';
-import { addQueryArgs } from '@wordpress/url';
-import { decodeEntities } from '@wordpress/html-entities';
 import { addFilter } from '@wordpress/hooks';
 
 /**
  * Internal dependencies
  */
 import Layout from './components/layout';
 import './store';
+import fetchLinkSuggestions from './utils/fetch-link-suggestions';
 
 function disableInsertingNonNavigationBlocks( settings, name ) {
 	if ( ! [ 'core/navigation', 'core/navigation-link' ].includes( name ) ) {
@@ -66,81 +62,6 @@ const removeNavigationBlockEditUnsupportedFeatures = createHigherOrderComponent(
 	'removeNavigationBlockEditUnsupportedFeatures'
 );
 
-/**
- * Fetches link suggestions from the API. This function is an exact copy of a function found at:
- *
- * packages/editor/src/components/provider/index.js
- *
- * It seems like there is no suitable package to import this from. Ideally it would be either part of core-data.
- * Until we refactor it, just copying the code is the simplest solution.
- *
- * @param {string} search
- * @param {Object} [searchArguments]
- * @param {number} [searchArguments.isInitialSuggestions]
- * @param {number} [searchArguments.type]
- * @param {number} [searchArguments.subtype]
- * @param {Object} [editorSettings]
- * @param {boolean} [editorSettings.disablePostFormats=false]
- * @return {Promise<Object[]>} List of suggestions
- */
-const fetchLinkSuggestions = (
-	search,
-	{ isInitialSuggestions, type, subtype } = {},
-	{ disablePostFormats = false } = {}
-) => {
-	const perPage = isInitialSuggestions ? 3 : 20;
-
-	const queries = [];
-
-	if ( ! type || type === 'post' ) {
-		queries.push(
-			apiFetch( {
-				path: addQueryArgs( '/wp/v2/search', {
-					search,
-					per_page: perPage,
-					type: 'post',
-					subtype,
-				} ),
-			} ).catch( () => [] ) // fail by returning no results
-		);
-	}
-
-	if ( ! type || type === 'term' ) {
-		queries.push(
-			apiFetch( {
-				path: addQueryArgs( '/wp/v2/search', {
-					search,
-					per_page: perPage,
-					type: 'term',
-					subtype,
-				} ),
-			} ).catch( () => [] )
-		);
-	}
-
-	if ( ! disablePostFormats && ( ! type || type === 'post-format' ) ) {
-		queries.push(
-			apiFetch( {
-				path: addQueryArgs( '/wp/v2/search', {
-					search,
-					per_page: perPage,
-					type: 'post-format',
-					subtype,
-				} ),
-			} ).catch( () => [] )
-		);
-	}
-
-	return Promise.all( queries ).then( ( results ) => {
-		return map( flatten( results ).slice( 0, perPage ), ( result ) => ( {
-			id: result.id,
-			url: result.url,
-			title: decodeEntities( result.title ) || __( '(no title)' ),
-			type: result.subtype || result.type,
-		} ) );
-	} );
-};
-
 export function initialize( id, settings ) {
 	if ( ! settings.blockNavMenus ) {
 		addFilter(
@@ -168,10 +89,8 @@ export function initialize( id, settings ) {
 		__experimentalRegisterExperimentalCoreBlocks();
 	}
 
-	settings.__experimentalFetchLinkSuggestions = partialRight(
-		fetchLinkSuggestions,
-		settings
-	);
+	settings.__experimentalFetchLinkSuggestions = () =>
+		fetchLinkSuggestions( settings );
 
 	render(
 		<Layout blockEditorSettings={ settings } />,

packages/edit-navigation/src/utils/fetch-link-suggestions.js

@@ -0,0 +1,86 @@
+/**
+ * WordPress dependencies
+ */
+import apiFetch from '@wordpress/api-fetch';
+import { addQueryArgs } from '@wordpress/url';
+/**
+ * External dependencies
+ */
+import { flatten, slice, map as _map, flow } from 'lodash';
+import { decodeEntities } from '@wordpress/html-entities';
+import { __ } from '@wordpress/i18n';
+
+// curried map operator with flipped arguments
+const map = ( mapFunction ) => ( array ) => _map( array, mapFunction );
+
+const toSuggestionLinkObj = ( { id, url, title, subType, type } ) => ( {
+	id,
+	url,
+	title: decodeEntities( title ) || __( '(no title)' ),
+	type: subType || type,
+} );
+const toApiFetchBody = ( { search, subtype, perPage } ) => ( linkType ) => ( {
+	path: addQueryArgs( '/wp/v2/search', {
+		search,
+		per_page: perPage,
+		type: linkType,
+		subtype,
+	} ),
+} );
+// eslint-disable-next-line no-console
+const exceptionHandler = ( e ) => ( console.error( e ), [] );
+const getAllLinkTypes = ( disablePostFormats ) => {
+	const baseLinkTypes = [ 'post', 'term' ];
+	return disablePostFormats
+		? baseLinkTypes
+		: [ ...baseLinkTypes, 'post-format' ];
+};
+/**
+ * Fetches link suggestions from the API. This function is an exact copy of a function found at:
+ *
+ * packages/editor/src/components/provider/index.js
+ *
+ * It seems like there is no suitable package to import this from. Ideally it would be either part of core-data.
+ * Until we refactor it, just copying the code is the simplest solution.
+ *
+ * @param {string} search
+ * @param {Object} [searchArguments]
+ * @param {number} [searchArguments.isInitialSuggestions]
+ * @param {number} [searchArguments.type]
+ * @param {number} [searchArguments.subtype]
+ * @param {Object} [editorSettings]
+ * @param {boolean} [editorSettings.disablePostFormats=false]
+ * @return {Promise<Object[]>} List of suggestions
+ */
+export default (
+	search,
+	{ isInitialSuggestions, type, subtype } = {},
+	{ disablePostFormats = false } = {}
+) => {
+	const perPage = isInitialSuggestions ? 3 : 20;
+	const typesOfLinksToFetch = type
+		? [ type ]
+		: getAllLinkTypes( disablePostFormats );
+
+	// assign piped functions producing api call
+	const toReqBody = flow( [
+		toApiFetchBody( { search, subtype, perPage } ),
+		apiFetch,
+		( promise ) => promise.catch( exceptionHandler ),
+	] );
+
+	// assign piped functions producing suggestion links objects from server response data
+	const toSuggestionLinksObjects = flow( [
+		flatten,
+		( x ) => slice( x, 0, perPage ),
+		toSuggestionLinkObj,
+	] );
+
+	// for each link type, build transformations describing how to make a call to API and then format response
+	const fromLinkTypeToSuggestionLinksObjects = map(
+		[ toReqBody, async ( x ) => await x, toSuggestionLinksObjects ],
+		map
+	);
+
+	return flow( fromLinkTypeToSuggestionLinksObjects )( typesOfLinksToFetch );
+};