src/hero.mjs: interceptors.contentType(): Generate body from status when missing

2 files changed, 44 insertions, 13 deletions

diff --git a/src/hero.mjs b/src/hero.mjs
index 5169284..b378887 100644
--- a/src/hero.mjs
+++ b/src/hero.mjs
@@ -71,15 +71,23 @@ export const interceptorsFn = ({
 	},
 	contentType: async (req, next) => {
 		const response = await next(req);
-		const [mimeType, body] = typeof response.body === "string" ?
-			["text/html",        response.body] :
-			["application/json", JSON.stringify(response.body) || ""];
+		const { status, body, headers } = response;
+		assert.equal(typeof status, "number");
+		const mappings = {
+			string:    () => [ "text/html",        body                             ],
+			undefined: () => [ "text/plain",       http.STATUS_CODES[status] + "\n" ],
+			FALLBACK:  () => [ "application/json", JSON.stringify(body)             ],
+		};
+		const type = typeof body;
+		assert.notEqual(type, "FALLBACK");
+		const [mimeType, renderedBody] =
+			(mappings[type] || mappings.FALLBACK)();
 		return {
 			...response,
-			body,
+			body: renderedBody,
 			headers: {
 				"Content-Type": mimeType,
-				"Content-Length": Buffer.byteLength(body),
+				"Content-Length": Buffer.byteLength(renderedBody),
 				...(response.headers || {})
 			},
 		};
diff --git a/tests/js/hero.mjs b/tests/js/hero.mjs
index 1c34738..8d8f811 100644
--- a/tests/js/hero.mjs
+++ b/tests/js/hero.mjs
@@ -247,7 +247,7 @@ const test_interceptorsFn = async t => {
 			assert.deepEqual(
 				contents.map(o => u.dissoc(o, "timings")),
 				[
-					{ ...req, type: "in-request"  },
+					{ ...req, type: "in-request" },
 					{ id: req.id, status, type: "in-response" },
 				],
 			);
@@ -261,20 +261,31 @@ const test_interceptorsFn = async t => {
 		t.start("interceptorsFn().contentType()");
 
 		await t.test("empty values", async () => {
+			await assert.rejects(
+				async () => await interceptorsFn().contentType({}, next),
+				assert.AssertionError,
+			);
 			assert.deepEqual(
-				await interceptorsFn().contentType({}, next),
+				await interceptorsFn().contentType({
+					status: 202,
+				}, next),
 				{
-					body: "",
+					status: 202,
+					body: "Accepted\n",
 					headers: {
-						"Content-Type": "application/json",
-						"Content-Length": 0,
+						"Content-Type": "text/plain",
+						"Content-Length": 9,
 					},
 				},
 			);
 
 			assert.deepEqual(
-				await interceptorsFn().contentType({ body: "" }, next),
+				await interceptorsFn().contentType({
+					status: 200,
+					body: "",
+				}, next),
 				{
+					status: 200,
 					body: "",
 					headers: {
 						"Content-Type": "text/html",
@@ -286,8 +297,12 @@ const test_interceptorsFn = async t => {
 
 		await t.test("body values", async () => {
 			assert.deepEqual(
-				await interceptorsFn().contentType({ body: { a: 1 }}, next),
+				await interceptorsFn().contentType({
+					status: 201,
+					body: { a: 1 },
+				}, next),
 				{
+					status: 201,
 					body: `{"a":1}`,
 					headers: {
 						"Content-Type": "application/json",
@@ -297,8 +312,12 @@ const test_interceptorsFn = async t => {
 			);
 
 			assert.deepEqual(
-				await interceptorsFn().contentType({ body: "<br />" }, next),
+				await interceptorsFn().contentType({
+					status: 200,
+					body: "<br />",
+				}, next),
 				{
+					status: 200,
 					body: "<br />",
 					headers: {
 						"Content-Type": "text/html",
@@ -311,6 +330,7 @@ const test_interceptorsFn = async t => {
 		await t.test("header values preference", async () => {
 			assert.deepEqual(
 				await interceptorsFn().contentType({
+					status: 503,
 					body: "",
 					headers: {
 						"Content-Type": "we have preference",
@@ -318,6 +338,7 @@ const test_interceptorsFn = async t => {
 					},
 				}, next),
 				{
+					status: 503,
 					body: "",
 					headers: {
 						"Content-Type": "we have preference",
@@ -330,12 +351,14 @@ const test_interceptorsFn = async t => {
 		await t.test("headers get propagated", async () => {
 			assert.deepEqual(
 				await interceptorsFn().contentType({
+					status: 500,
 					body: "",
 					headers: {
 						"My": "Header",
 					},
 				}, next),
 				{
+					status: 500,
 					body: "",
 					headers: {
 						"My": "Header",