How to handle JSON error message

Question

I am a complete newbie with JavaScript and jQuery.

When I request my API, I usually get JSON as follows:

{ "soc": 9271, "series": [ { "year": 2013, "estpay": 370 }, { "year": 2012, "estpay": 430 } ] } 

However, if my request is invalid, I will get JSON as follows:

 { "error": "Some message here . . . .." } 

So my question is: what is the syntax for detecting an error message and then setting the response type to IF / ELSE? those. if the error message does this. If the error message does not do something else.

Answer 1

You can try using a implemented JSON tool that has built-in methods.

Secondly, you can try and use this:

 if (response){ try{ a=JSON.parse(response); }catch(e){ alert(e); //error in the above string(in this case,yes)! } } 

Good luck

Answer 2

check if there is a first error

 // assume response is received as string var data = JSON.parse(response) ... if (data.error) { // handle error console.log(data.error); return; } // handle code normally ... 

Answer 3

 var o = JSON.parse(response); if('error' in o){ // error in response } 

Answer 4

Suppose the JSON object is stored in the result variable.

You can try something like this:

 var result = JSON.parse(myQuery()); // myQuery() is the function that executes your query if (result.error) { alert("Error message here !"); } else { alert("Hallelujah !"); } 

Answer 5

Checking for the error key in your response data will do the job until now, but in order for your API to comply with the REST protocol and more scalable / dynamic, I would base the error handling on the HTTP status code and messages. You can refer to this list to find out what the valid answer is and what each status code means. https://en.wikipedia.org/wiki/List_of_HTTP_status_codes

Here is a quick example of how to handle status code in jQuery:

 $.ajax({ statusCode: { 500: function(xhr) { if(window.console) console.log(xhr.responseText); } } }); 

In addition, you should also parse JSON to see if this is true, for example, Michael Ido suggested

Answer 6

It can be a good structure.

 try { data = JSON.parse(response); } catch(e) { data = false; } if(!data || data.error) { // handel error } else { // data is good } 

Answer 7

Thanks for the very quick answers. I tried to implement your suggestions, but I fail because of the lack of knowledge of newcomers. I gave an example of the code that I am working with below.

I just need the JSON from $ .get to be checked for the word "error".

If an “error” appears, I need var nipay to contain something like “Not Available”.

Otherwise, var nipay = maxBy ("year", data.series) .estpay

 $.get("http://my_api_url", function(data) { var nipay = maxBy("year", data.series).estpay ; $("#box1").html("<p><b>NI:</b> " + nipay + " GBP/week </p>") });