Question

I have a JSON file my.json with the following content:

{   
    title: "My Title",
}

And, a jQuery snippet to read it:

var reading_file = $.getJSON('my.json', function (data) {
  alert('Success.');
}

The alert() inside the callback never gets called because there is an error in the JSON file i.e. title is not wrapped as a string, as in"title".

When run on the browser (Chrome), this did not throw an error or any indication of something was wrong. To be specific, my.json was retrieved properly (status code: 200), although reading_file.state() is always pending.

My questions:

1. What is a good way to catch this type of error i.e. invalid JSON data / syntax?
2. Inside the function (data) { alert ... } callback, what does this refer to?

Thanks.

Answer 1

From the docs

In jQuery 1.4 the JSON data is parsed in a strict manner; any malformed JSON is rejected and a parse error is thrown

You would use the error handler to catch the error. Something like

var reading_file = $.getJSON('my.json', function (data) {
  alert('Success.');
}).error(function(jqXHR, textStatus, errorThrown) {
    alert("Stop! Error time!");
});

Update

As mentioned by Ian, this in the success callback context is not an Ajax Event. It appears to be the configuration object passed to $.ajax().