Fix asset url path for development (#13038)

* fix/asset-url-path

dotcom-rendering/src/lib/assets.test.ts

@@ -2,6 +2,7 @@ import { readFileSync } from 'node:fs';
 import { BUILD_VARIANT } from '../../webpack/bundles';
 import {
 	APPS_SCRIPT,
+	BASE_URL_DEV,
 	decideAssetOrigin,
 	getModulesBuild,
 	getPathFromManifest,
@@ -27,9 +28,9 @@ describe('decideAssetOrigin for stage', () => {
 		);
 	});
 	it('DEV', () => {
-		expect(decideAssetOrigin('DEV')).toEqual('/');
-		expect(decideAssetOrigin('dev')).toEqual('/');
-		expect(decideAssetOrigin(undefined)).toEqual('/');
+		expect(decideAssetOrigin('DEV', true)).toEqual(BASE_URL_DEV);
+		expect(decideAssetOrigin('dev', true)).toEqual(BASE_URL_DEV);
+		expect(decideAssetOrigin(undefined, false)).toEqual('/');
 	});
 });
 

dotcom-rendering/src/lib/assets.ts

@@ -9,18 +9,28 @@ interface AssetHash {
 	[key: string]: string;
 }
 
+export const BASE_URL_DEV = 'http://localhost:3030/';
+
 export type AssetOrigin =
 	| 'https://assets.guim.co.uk/'
 	| 'https://assets-code.guim.co.uk/'
+	| typeof BASE_URL_DEV
 	| '/';
 
 /**
  * Decides the url to use for fetching assets
  *
  * @param {'PROD' | 'CODE' | undefined} stage the environment code is executing in
- * @returns {string}
+ * @param {boolean} isDev whether the environment is development
+ * @returns {AssetOrigin}
  */
-export const decideAssetOrigin = (stage: string | undefined): AssetOrigin => {
+export const decideAssetOrigin = (
+	stage: string | undefined,
+	isDev?: boolean,
+): AssetOrigin => {
+	if (isDev) {
+		return BASE_URL_DEV;
+	}
 	switch (stage?.toUpperCase()) {
 		case 'PROD':
 			return 'https://assets.guim.co.uk/';
@@ -33,7 +43,7 @@ export const decideAssetOrigin = (stage: string | undefined): AssetOrigin => {
 
 const isDev = process.env.NODE_ENV === 'development';
 
-export const ASSET_ORIGIN = decideAssetOrigin(process.env.GU_STAGE);
+export const ASSET_ORIGIN = decideAssetOrigin(process.env.GU_STAGE, isDev);
 
 const isAssetHash = (manifest: unknown): manifest is AssetHash =>
 	isObject(manifest) &&