Im using the following javascript. it writes fine until it gets to a result which doesn't have a value. in console log it shows this

Uncaught TypeError: Cannot read property 'text' of null

but my script below doesn't seem to work

            var checkCaption = photo.caption.text;
            if (checkCaption == null) {
                caption = 'meh';
            } else {
                caption = photo.caption.text;
            }

Im using the following javascript. it writes fine until it gets to a result which doesn't have a value. in console log it shows this

Uncaught TypeError: Cannot read property 'text' of null

but my script below doesn't seem to work

            var checkCaption = photo.caption.text;
            if (checkCaption == null) {
                caption = 'meh';
            } else {
                caption = photo.caption.text;
            }

• javascript
• json

5 Answers 5

In your example, photo.caption is null, so your code breaks on the photo.caption.text call, before the check is done.

var caption;

if(photo.caption != null) { // Covers 'undefined' as well
  caption = photo.caption.text;
} else {
  caption = "meh";
}

In my case i use the JSON.stringify to check I have received {} (null) response from the REST server:

 if (JSON.stringify(response.data)=='{}') {
      //the response is null
 }
 else {
      //the response of JSON is not null
 }

It works fine for me to check if the response is null or not.

For me the check of length of the json object resolved the issue -

   if Object.keys(jsonobj).length == 0){
     // JSON object is null
    }
   else {
     // JSON object has data 
    }

I know it's pretty late but it might help someone else. you can do this in one line

var checkCaption = photo.caption?.text ?? 'meh';

You can also use

   if ("caption" in photo) {
    caption = photo.caption?.text
   } else {
    caption = "meh"
   }