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up vote 0 down vote favorite

I have a JSON file containing some data I d like to access on my AngularJS website. Now what I want is to get only one object from the array. So I d like for example Item with id 1.

The data looks like this:

{ "results": [
    {
        "id": 1,
        "name": "Test"
    },
    {
        "id": 2,
        "name": "Beispiel"
    },
    {
        "id": 3,
        "name": "Sample"
    }
] }

I d like to load the data with AngularJS $http functionality like this:

$http.get("data/SampleData.json");

which is working. But how can I now get a specific data object (by id) from the array I get from $http.get ?

Thanks in advance for your help.

Greets Marc

share|improve this question
 
Have you given it a go yourself? If so, can we see what you came up with? –  simonlchilds Oct 25 '13 at 12:38
 
Well I have no idea which way would be the best using AngularJS. What I dont like is to iterate over the array and do a equals on the id. Maybe there is a better way? –  marcbaur Oct 25 '13 at 12:40
 
You should rely on underscorejs or similar libraries for such processing. AngularJS is MVVM framework and may not have api for this. –  Vijay Pande Oct 25 '13 at 12:46
 
@marcbaur - you have to iterate the array. Even if you use underscore, or something similar, it's functions, behind the scenes, are just iterating. –  Adam Oct 25 '13 at 13:00
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3 Answers

up vote 2 down vote accepted

The only way to do this is to iterate over the array. Obviously if you are sure that the results are ordered by id you can do a binary search

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1  
... I really hope after reading this answer people don't think it's a good idea to sort an array then do a binary search. Binary search is clever, sure, but only if the array is already sorted, and in reality is: 1. easy to poorly implement, 2. Harder to read if poorly implemented. –  blesh Oct 25 '13 at 14:51
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up vote 2 down vote

You can just loop over your array:

var doc = { /* your json */ };

function getById(arr, id) {
    for (var d = 0, len = arr.length; d < len; d += 1) {
        if (arr[d].id === id) {
            return arr[d];
        }
    }
}

var doc_id_2 = getById(doc.results, 2);

If you don't want to write this messy loops, you can consider using underscore.js or Lo-Dash (example in the latter):

var doc_id_2 = _.filter(doc.results, {id: 2})[0]
share|improve this answer
 
Thanks for your help. I think that will do the trick. –  marcbaur Oct 25 '13 at 13:26
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up vote 0 down vote

Unfortunately (unless I'm mistaken), I think you need to iterate over the results object. 

for(var i = 0; i < results.length; i += 1){
    var result = results[i];
    if(result.id === id){
        return result;
    }
}

At least this way it will break out of the iteration as soon as it finds the correct matching id.

share|improve this answer
 
Not a good practice to use for..in over arrays. –  kamituel Oct 25 '13 at 13:11
 
Why? Do you have anything to back that up? –  simonlchilds Oct 25 '13 at 14:27
 
Well, do you know what..? I just went off to re-read Javascript - the good parts to counter your argument and I am wrong! For all this time I've been doing it wrong! It hasn't caused me any problems though... yet. I've updated my answer. –  simonlchilds Oct 25 '13 at 14:34
 
Glad I helped :) –  kamituel Oct 25 '13 at 14:39
1  
This is why I love SO. Everyday is a learning day. –  simonlchilds Oct 25 '13 at 14:41
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