CODEWITHSUNDEEP
javascriptjquery
Bizzy
Bizzy

Reputation: 71

How to process JSON error message

I am a complete beginner with JavaScript and jQuery.

When I query my API I will normally get JSON like this:

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

However if my query is invalid I will get JSON like this:

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

So my question is - what is the syntax to detect the error message and then set up an IF / ELSE type of response? i.e. If error message do this.. If no error message do something else.

Upvotes: 5

Views: 855

Answers (7)

Bizzy
Bizzy

Reputation: 71

Thanks for the very quick replies. I have been trying to implement your suggestions but I'm not succeeding due to beginners ignorance. I have put a 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 "error" appears then 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>")
});

Upvotes: -1

Alex
Alex

Reputation: 565

Checking if there is an "error" key in your response data will do the job for now but for the sake of making your API conforming to the REST protocol and more scalable/dynamic I would base the error handling on HTTP status code and messages. You can refer yourself to this list to see what is a valid response and what each status code means. https://en.wikipedia.org/wiki/List_of_HTTP_status_codes

Here's a short example on how to handle the status code in jQuery:

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

Additionally, you should also parse the JSON to see if it is valid, like Ido Michael suggested

Upvotes: 0

LukasGuptaLeary
LukasGuptaLeary

Reputation: 121

This might be a good structure

try {
    data = JSON.parse(response);
} catch(e) {
    data = false;
}

if(!data || data.error) {
    // handel error
} else {
    // data is good
}

Upvotes: 0

devio
devio

Reputation: 1169

Let's assume that the JSON object is stored in the variable result.

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 !");
}

Upvotes: 0

Joseph Dan
Joseph Dan

Reputation: 94

check if there's an error first

// assume response is received as string
var data = JSON.parse(response) 
...

if (data.error) {
    // handle error
    console.log(data.error);
    return;
}

// handle code normally
...

Upvotes: 1

Vladimir G.
Vladimir G.

Reputation: 885

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

Upvotes: 0

Ido Michael
Ido Michael

Reputation: 109

You can try using an implemented JSON tool which has this methods built inside.

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!

Upvotes: 1

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