Use noop as next middleware in the last middleware in the stack

Author: mmtr

package-lock.json

@@ -24,7 +24,8 @@
 		"@babel/runtime": "^7.0.0",
 		"@wordpress/hooks": "file:../hooks",
 		"@wordpress/i18n": "file:../i18n",
-		"@wordpress/url": "file:../url"
+		"@wordpress/url": "file:../url",
+		"lodash": "^4.17.10"
 	},
 	"publishConfig": {
 		"access": "public"

packages/api-fetch/package.json

@@ -1,3 +1,8 @@
+/**
+ * External dependencies
+ */
+import { noop } from 'lodash';
+
 /**
  * WordPress dependencies
  */
@@ -136,14 +141,15 @@ function apiFetch( options ) {
 
 	const runMiddleware = ( index ) => ( nextOptions ) => {
 		const nextMiddleware = steps[ index ];
+		let next;
 
 		if ( steps.length > ( index + 1 ) ) {
-			const next = runMiddleware( index + 1 );
-			return nextMiddleware( nextOptions, next );
+			next = runMiddleware( index + 1 );
+		} else {
+			next = noop;
 		}
 
-		// Next middleware is the last one, so no next arg is passed
-		return nextMiddleware( nextOptions );
+		return nextMiddleware( nextOptions, next );
 	};
 
 	return runMiddleware( 0 )( options );

packages/api-fetch/src/index.js

@@ -1,3 +1,8 @@
+/**
+ * External dependencies
+ */
+import { noop } from 'lodash';
+
 /**
  * Internal dependencies
  */
@@ -193,6 +198,6 @@ describe( 'apiFetch', () => {
 
 		expect( window.fetch ).not.toHaveBeenCalled();
 
-		expect( customFetchHandler ).toHaveBeenCalledWith( { path: '/random?_locale=user' } );
+		expect( customFetchHandler ).toHaveBeenCalledWith( { path: '/random?_locale=user' }, noop );
 	} );
 } );