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

1 files changed, 13 insertions, 5 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 || {})
 			},
 		};