fix(rest): Fix parameter description

Avoid describing parameters if debug is not on
Check undefined parameters (not decorated with @param) in the array

Author: raymondfeng

packages/rest/src/router/routing-table.ts

@@ -89,13 +89,15 @@ export class RoutingTable {
   registerRoute(route: RouteEntry) {
     // TODO(bajtos) handle the case where opSpec.parameters contains $ref
     // See https://github.com/strongloop/loopback-next/issues/435
-    debug(
-      'Registering route %s %s -> %s(%s)',
-      route.verb,
-      route.path,
-      route.describe(),
-      describeOperationParameters(route.spec),
-    );
+    if (debug.enabled) {
+      debug(
+        'Registering route %s %s -> %s(%s)',
+        route.verb,
+        route.path,
+        route.describe(),
+        describeOperationParameters(route.spec),
+      );
+    }
     this._routes.push(route);
   }
 
@@ -322,6 +324,6 @@ export class ControllerRoute extends BaseRoute {
 
 function describeOperationParameters(opSpec: OperationObject) {
   return ((opSpec.parameters as ParameterObject[]) || [])
-    .map(p => p.name)
+    .map(p => (p && p.name) || '')
     .join(', ');
 }

packages/rest/test/unit/router/routing-table.test.ts

@@ -8,6 +8,9 @@ import {
   parseRequestUrl,
   RoutingTable,
   ControllerRoute,
+  getControllerSpec,
+  param,
+  get,
 } from '../../..';
 import {expect, ShotRequestOptions, ShotRequest} from '@loopback/testlab';
 import {anOpenApiSpec} from '@loopback/openapi-spec-builder';
@@ -30,6 +33,27 @@ describe('RoutingTable', () => {
     );
   });
 
+  it('does not fail if some of the parameters are not decorated', () => {
+    class TestController {
+      @get('/greet')
+      greet(prefix: string, @param.query.string('message') message: string) {
+        return prefix + ': ' + message;
+      }
+    }
+    const spec = getControllerSpec(TestController);
+    const table = new RoutingTable();
+    table.registerController(TestController, spec);
+    const paths = table.describeApiPaths();
+    const params = paths['/greet']['get'].parameters;
+    expect(params).to.have.property('length', 2);
+    expect(params[0]).to.be.undefined();
+    expect(params[1]).to.have.properties({
+      name: 'message',
+      in: 'query',
+      type: 'string',
+    });
+  });
+
   it('finds simple "GET /hello" endpoint', () => {
     const spec = anOpenApiSpec()
       .withOperationReturningString('get', '/hello', 'greet')