feat: Added a way to handle 404 error from IlcAppSdk (#33)

* feat: handle 404 error

* fix: handling status codes

src/app/index.ts

@@ -72,6 +72,22 @@ export default class IlcAppSdk implements IIlcAppSdk {
         const intlAdapter = this.adapter.intl ? this.adapter.intl : defaultIntlAdapter;
         this.intl = new IlcIntl(this.appId, intlAdapter);
     }
+    /**
+     * Isomorphic method to render 404 page.
+     * At SSR in processResponse it sets 404 status code to response.
+     * At CSR it triggers global event which ILC listens and renders 404 page.
+     */
+    render404 = () => {
+        if (this.adapter.setStatusCode) {
+            this.adapter.setStatusCode(404);
+        } else {
+            window.dispatchEvent(
+                new CustomEvent('ilc:404', {
+                    detail: { appId: this.appId },
+                }),
+            );
+        }
+    };
 
     unmount() {
         this.intl.unmount();

src/app/interfaces/common.ts

@@ -27,8 +27,12 @@ export interface AppSdkAdapter {
     /** Unique application ID, if same app will be rendered twice on a page - it will get different IDs */
     appId: string;
     intl: IntlAdapter | null;
+    setStatusCode: (code: number) => void;
+    getStatusCode: () => number | undefined;
 }
 
+export type Render404 = () => void;
+
 export interface IntlConfig {
     locale?: string;
     currency?: string;

src/server/IlcSdk.ts

@@ -55,6 +55,8 @@ export class IlcSdk {
             originalUri = '/';
         }
 
+        let statusCode: number | undefined;
+
         return {
             getCurrentReqHost: () => host,
             getCurrentReqUrl: () => requestedUrls.requestUrl,
@@ -63,6 +65,10 @@ export class IlcSdk {
             getCurrentPathProps: () => passedProps,
             appId,
             intl: this.parseIntl(req),
+            setStatusCode: (code) => {
+                statusCode = code;
+            },
+            getStatusCode: () => statusCode,
         };
     }
 
@@ -72,6 +78,11 @@ export class IlcSdk {
      * **WARNING:** this method should be called before response headers were send.
      */
     public processResponse(reqData: types.RequestData, res: ServerResponse, data?: types.ResponseData): void {
+        const statusCode = reqData.getStatusCode();
+        if (statusCode) {
+            res.statusCode = statusCode;
+        }
+
         if (!data) {
             return;
         }

test/server/IlcSdk.spec.ts

@@ -292,6 +292,19 @@ describe('IlcSdk', () => {
             );
         });
 
+        it('should set 404 status code', () => {
+            const NotFound = 404;
+
+            const req = new MockReq(merge({}, defReq));
+            const res = new MockRes();
+
+            const pRes = ilcSdk.processRequest(req);
+            pRes.setStatusCode(NotFound);
+            ilcSdk.processResponse(pRes, res);
+
+            expect(res.statusCode).to.eq(NotFound);
+        });
+
         describe('appAssets', () => {
             it('should handle absolute URLs', () => {
                 const req = new MockReq(merge({}, defReq));