How to check if the response received from server is html or json and find the html form by name in extjs?

Question

I have an extjs application that sends an ajax request to the backend. The backend will send the objects which are json format if it is an active session and a html page if the session is inactive

I want to identify if it is a json or html type that is received in the response and perform further actions accordingly

Here is the sample code:

Ext.Ajax.Request({
   url: "localhost",
   scope: this,
   method: "POST"
   success: 'successongettingdata'
})

successongettingdata : function(connection,response) {
   //check for response if html or json and do actions accordingly
   //how to extract from response that if it is json or html or string
   //if it is html, get form by its name
}

Answer 1

Referring to @incutonez, You can check Content-Type header from returned request.

Ext.Ajax.request({
   url: "localhost",
   scope: this,
   method: "POST",
   success: 'successongettingdata'
});

successongettingdata : function(connection, response) {
   if(connection.getResponseHeader("Content-Type").includes("text/html")) {
     
   } else if(connection.getResponseHeader("Content-Type").includes("application/json")) {
   
   }

}

Or you can try to decode returned data if Content-Type is wrong.

successongettingdata : function(connection, response) {
   try {
       let decodeResponse = Ext.decode(connection.responseText);
       //is json
   } catch (e) {
       //isn't json
   }
}