Looping through nested arrays in Javascript

Question

So I have an API that returns JSON data

Example JSON:

{
   "result":"OK",
   "data":[
      {
         "number":"613-555-5555",
         "calls":30
      },
      {
         "number":"613-666-5555",
         "calls":100
      }
   ]
}

I am trying to output this using javascript to show the following

[number, calls],[number, calls]

var response = response.data;
var length = response.length;
alert(data[0].number);
alert(data[0].calls);

for (var i = 0; i < data.length; i++) {
    var arrayItem = data[i];
    document.write(arrayItem);
}

I should mention that the two alerts at the top work for getting the first position in the array. — Andrew Goldenberg, Aug 01 '13 at 19:34
You refer to `data` in one place, and `response` in the other. Which is it? — Travis J, Aug 01 '13 at 19:35
@TravisJ `response` is the object you see up there. `data` is one of its properties. — Asad Saeeduddin, Aug 01 '13 at 19:37
`document.write` will overwrite the document on every iteration, so it's no suprise if this doesn't work ? — adeneo, Aug 01 '13 at 19:37
@Asad - Look again. `data` is not referenced and yet is said to exist. You cannot reference a property by simply using its name. By defining `var response = response.data;` does mean you can magically use `data` as a variable name. — Travis J, Aug 01 '13 at 19:38
possible duplicate of [Access / process (nested) objects, arrays or JSON](http://stackoverflow.com/questions/11922383/access-process-nested-objects-arrays-or-json) — Andrew Whitaker, Aug 01 '13 at 19:38
@Asad - More than likely this was meant: `var data = response.data;`, which is why I asked for clarification. — Travis J, Aug 01 '13 at 19:39
var data = response.data; response.data is the data from an ajax call. — Andrew Goldenberg, Aug 01 '13 at 19:40
So, again, what's your complete (minimal) code, and what's the current output? — Karoly Horvath, Aug 01 '13 at 19:41
@AndrewGoldenberg: Update your question to provide additional information instead of just posting it in comments. — , Aug 01 '13 at 19:42

Asad Saeeduddin · Accepted Answer · 2013-08-01T19:56:21.560

2

This is simply a question of mapping your data to the desired format:

var final = response.data.map(function(item) {
    return [item.number, item.calls];
});
console.log(final);

Here is a demo: http://jsfiddle.net/c8UQg/

EDIT:

I didn't realise you were looking for a string representation (I thought you wanted an array). If that is the case, please disregard the above.

edited Aug 01 '13 at 19:56

answered Aug 01 '13 at 19:38

Asad Saeeduddin

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for the sake of clarity in code, I'd personally be a fan of seeing `function(data){ return [data.number, data.calls];}` simply because it's easier to read. – Chase Florell Aug 01 '13 at 19:51
1

@ChaseFlorell `data` is being used to refer to a property of the original object, so I think using `data` to refer to the elements of `response.data` might be slightly confusing. I've tried to improve the naming nevertheless. – Asad Saeeduddin Aug 01 '13 at 19:56

score 0 · Answer 2 · answered Aug 01 '13 at 19:42

0

If you like everything the way it is code wise, and just want to fix the error, then I suggest changing

var response = response.data;

to

var data = response.data;

Also, for the sake of debugging, change

document.write(arrayItem);

to

console.log(arrayItem);

http://jsfiddle.net/GptRW/

answered Aug 01 '13 at 19:42

Chase Florell

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According to the comments, that's what OP is actually doing. The question states that the calls to `alert()` work, which means that the variable name in the original code is correct. The issue is therefore most likely the call to `document.write` after the page has loaded. – Aug 01 '13 at 19:44
not a fan of answering questions based on comments. The entire question should be asked in the question. Also, trying to access `data[0]` when there is no `data` object is going to be an issue beyond the `document.write` error. – Chase Florell Aug 01 '13 at 19:46

Looping through nested arrays in Javascript

2 Answers2