How to trigger jquery.ajax() error callback based on server response, not HTTP 500?

Question

By using jquery ajax function, I can do something like:

$.ajax({

  url: url,
  type: \'GET\',
  async: true,
  dataType: \'json\',
  data: data,

 success:          


        

Answer 1

This original question was posted years ago, and perhaps there are better ways of handling this now. Here's a suggestion to handle multiple types of errors, including the OP's question.

Input type (error) example #1

function handleError (type){
type = type || "Connection Issue";
 var value = "Error occurred: " + type;
 alert(value);
}

function checkIfError(response){
    if (response == "DB_ERROR") {
        handleError("Server error");
        throw new Error("JS died"); // optional, keep from running additional script
     }
}

var example = {

    success: function (response) {
        checkIfError(response); // check data if error msg
        // do stuff when proper data sent
        alert(response);

    }, error: handleError // connection error, call error msg
};

test1 = example['error']();

Input type (success:error) example #2

function handleError (type){
type = type || "Connection Issue";
 var value = "Error occurred: " + type;
 alert(value);
}

function checkIfError(response){
    if (response == "DB_ERROR") {
        handleError("Server error");
        throw new Error("JS died"); // optional, keep from running additional script
     }
}

var example = {

    success: function (response) {
        checkIfError(response); // check data if error msg
        // do stuff when proper data sent
        alert(response);

    }, error: handleError // connection error, call error msg
};


test2 = example['success']("DB_ERROR");

Input type (success) example #3

function handleError (type){
type = type || "Connection Issue";
 var value = "Error occurred: " + type;
 alert(value);
}

function checkIfError(response){
    if (response == "DB_ERROR") {
        handleError("Server error");
        throw new Error("JS died"); // optional, keep from running additional script
     }
}

var example = {

    success: function (response) {
        checkIfError(response); // check data if error msg
        // do stuff when proper data sent
        alert(response);

    }, error: handleError // connection error, call error msg
};


test3 = example['success']("Proper Response");

By using functions, if you have multiple calls in your scripts, you can simplify changes.

Have your PHP (or whatever server side code) return the response of "DB_ERROR" (or whatever you want) to trigger the error; allows you to do different things depending on the error.