Middleware send text/html instead of application/json

What I get from validation is this:

< HTTP/1.1 100 Continue
< HTTP/1.1 400 Bad Request
< X-Powered-By: Express
< X-Content-Type-Options: nosniff
< Content-Type: text/html; charset=utf-8
< Content-Length: 299
< Date: Wed, 27 Jul 2016 10:19:37 GMT
< Connection: keep-alive
* HTTP error before end of send, stop sending
< 
{&quot;status&quot;:400,&quot;statusText&quot;:&quot;Bad Request&quot;,&quot;errors&quot;:[{&quot;field&quot;:&quot;page&quot;,&quot;location&quot;:&quot;body&quot;,&quot;messages&quot;:[&quot;\&quot;page\&quot; must be larger than or equal to 1&quot;],&quot;types&quot;:[&quot;number.min&quot;]}]}
* Closing connection 0

How to change content-type and prevent html escaping?

[IrynaBu]

This saved me 😃 router.use((err, req,res,next)=>{ if (err instanceof ValidationError){ res.status(err.status).json(err); } else { res.send(err); } });

[ClintEsteMadera]

It is worth mentioning that this error handling middleware has to be defined after all the routes have been defined, otherwise, it won’t work.