diff --git a/examples/JsonPost.mjs b/examples/JsonPost.mjs
index 088d5ff89..cf8b28552 100644
--- a/examples/JsonPost.mjs
+++ b/examples/JsonPost.mjs
@@ -33,38 +33,17 @@ const app = uWS./*SSL*/App({
 
 /* Helper function for reading a posted JSON body */
 function readJson(res, cb, err) {
-  let buffer;
-  /* Register data cb */
-  res.onData((ab, isLast) => {
-    let chunk = Buffer.from(ab);
-    if (isLast) {
-      let json;
-      if (buffer) {
-        try {
-          json = JSON.parse(Buffer.concat([buffer, chunk]));
-        } catch (e) {
-          /* res.close calls onAborted */
-          res.close();
-          return;
-        }
-        cb(json);
-      } else {
-        try {
-          json = JSON.parse(chunk);
-        } catch (e) {
-          /* res.close calls onAborted */
-          res.close();
-          return;
-        }
-        cb(json);
-      }
-    } else {
-      if (buffer) {
-        buffer = Buffer.concat([buffer, chunk]);
-      } else {
-        buffer = Buffer.concat([chunk]);
-      }
+  /* collectBody gives the whole body at once, or null if it is bigger than 1 MB */
+  res.collectBody(1024 * 1024, (body) => {
+    let json;
+    try {
+      json = JSON.parse(Buffer.from(body));
+    } catch (e) {
+      /* Too big, invalid or empty: res.close calls onAborted */
+      res.close();
+      return;
     }
+    cb(json);
   });
 
   /* Register error cb */