demo 20-4-2026

utils/apiEnvelope.js

@@ -0,0 +1,65 @@
+function envelopeResponses(_req, res, next) {
+    const originalJson = res.json.bind(res);
+
+    res.json = (payload) => {
+        if (isApiEnvelope(payload)) {
+            return originalJson(payload);
+        }
+
+        const isError = res.statusCode >= 400;
+        const message = extractMessage(payload, isError);
+        const errors = extractErrors(payload, isError, message);
+        const data = isError ? null : payload;
+
+        return originalJson({
+            status: isError ? "error" : "success",
+            data,
+            message,
+            errors,
+        });
+    };
+
+    next();
+}
+
+function isApiEnvelope(payload) {
+    return Boolean(
+        payload &&
+        typeof payload === "object" &&
+        !Array.isArray(payload) &&
+        Object.prototype.hasOwnProperty.call(payload, "status") &&
+        Object.prototype.hasOwnProperty.call(payload, "data") &&
+        Object.prototype.hasOwnProperty.call(payload, "message") &&
+        Object.prototype.hasOwnProperty.call(payload, "errors")
+    );
+}
+
+function extractMessage(payload, isError) {
+    if (payload && typeof payload === "object" && !Array.isArray(payload)) {
+        if (typeof payload.message === "string" && payload.message.length) {
+            return payload.message;
+        }
+        if (typeof payload.error === "string" && payload.error.length) {
+            return payload.error;
+        }
+    }
+
+    return isError ? "Request failed" : "OK";
+}
+
+function extractErrors(payload, isError, message) {
+    if (!isError) return [];
+    if (payload && typeof payload === "object" && !Array.isArray(payload)) {
+        if (Array.isArray(payload.errors)) {
+            return payload.errors;
+        }
+        if (payload.error) {
+            return [payload.error];
+        }
+    }
+    return message ? [message] : [];
+}
+
+module.exports = {
+    envelopeResponses,
+};