feat(api): allow routing all email through fallback (#3509)

fluxer_api/pkgs/email/src/DomainRoutedEmailProvider.test.ts

@@ -30,6 +30,16 @@ describe('DomainRoutedEmailProvider', () => {
 		expect(result).toBe(route === 'primary');
 	});
 
+	it('sends every address through the fallback provider when the domains are *', async () => {
+		const primary = {sendEmail: vi.fn().mockResolvedValue(true)};
+		const fallback = {sendEmail: vi.fn().mockResolvedValue(true)};
+		const provider = new DomainRoutedEmailProvider(primary, fallback, ['*']);
+		await provider.sendEmail(message('[email protected]'));
+		await provider.sendEmail(message('[email protected]'));
+		expect(fallback.sendEmail).toHaveBeenCalledTimes(2);
+		expect(primary.sendEmail).not.toHaveBeenCalled();
+	});
+
 	it('never reaches either provider for a bounced address', async () => {
 		const primary = {sendEmail: vi.fn().mockResolvedValue(true)};
 		const fallback = {sendEmail: vi.fn().mockResolvedValue(true)};

fluxer_api/pkgs/email/src/DomainRoutedEmailProvider.ts

@@ -21,7 +21,7 @@ export class DomainRoutedEmailProvider implements IEmailProvider {
 			.slice(message.to.lastIndexOf('@') + 1)
 			.trim()
 			.toLowerCase();
-		const useFallback = this.fallbackDomains.has(domain);
+		const useFallback = this.fallbackDomains.has('*') || this.fallbackDomains.has(domain);
 		logger.debug({domain, provider: useFallback ? 'fallback' : 'primary'}, 'Routing email');
 		return (useFallback ? this.fallback : this.primary).sendEmail(message);
 	}