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This question already has an answer here:

Sorry if this question is a duplicate but I have to ask it. I am using prototype JS for reading JSON data from a file. JSON data looks like this;

{
    "metaData": {
        "date": "2014-10-06"
    },
    "listOf": [
        {
            "fname": "bill",
            "id": 23
        },
        {
            "fname": "tom",
            "id": 35
        },
        {
            "fname": "jerry",
            "id": 12
        },
        {
            "fname": "batman",
            "id": 68
        },
        {
            "fname": "superman",
            "id": 55
        },
        {
            "fname": "sp-m/super",
            "id": 55
        },
    ]
}

In my code I need to access "listOf" key/array and then I want to loop through each element and to sort those elements base on "fname" key. I am reading this data through an ajax request. Below is that code;

new Ajax.Request('/file.json', {
                    method:'get',
                    onSuccess: function(transport){
                        var json = transport.responseText.evalJSON();
                        console.log(json);
                    }
                });

Now the VAR JSON contains the require data but I don't know how to access "listOf" data and iterate through it.

I tried to use .each function like this;

json.list.each(alert);

but it only printed " object OBJECT".

Please give me some help to resolve this issue.

P.S: Please tyr to use prototype JS for an answer but no Jquery.

share|improve this question

marked as duplicate by Felix Kling Oct 7 '14 at 19:56

This question has been asked before and already has an answer. If those answers do not fully address your question, please ask a new question.
    
Assuming that you actually used json.listOf.each(alert), then that's the expected result - the same result that e.g. alert({ "fname": "bill", "id": 23 }) would have. –  Bergi Oct 7 '14 at 19:45

1 Answer 1

up vote 1 down vote accepted

You can access the listOf collection property using its name:

json.listOf

So if you wanted to sort the array you could try using the .sort() javascript method:

json.listOf.sort(function(a, b) {
    if (a.fname > b.fname) {
        return 1;
    } else if (a.fname < b.fname) {
        return -1;
    }
    return 0;
});

// At this stage json.listOf will contain the sorted in-place array using the `fname` property

and here's a sample jsfiddle illustrating this in action.

share|improve this answer
    
Thanks for your reply. I just edited the "listOf" property with an extra value. In that the sort does not sort the elements/list properly. It place the "sp-m/super" before "superman". Any idea how this can be fix? you can try this your jsfiddle code. –  Capri82 Oct 7 '14 at 19:58
    
Why are you surprised that sp-m or super is placed alphabetically before superman? That's how alphabetical sort works. If you want to perform some custom sorting that feel free to update the anonymous function passed to the .sort() method to suit your custom needs. –  Darin Dimitrov Oct 7 '14 at 20:04
    
:) I am not surprised but not understood the sorting completely. Anyway can you atleast put me in right direction that how can i put the words like "superman" before "sp-m/super". Some hints will be enough. –  Capri82 Oct 7 '14 at 20:17
    
You wanna do inverse alphabetical order? Then just change the if condition. If not please specify what are the precise rules you wanna be sorting upon. Without knowing the precise rules it's quite unlikely you will be able to implement them. –  Darin Dimitrov Oct 7 '14 at 20:23
    
What you have shown in your demo is correct. Only thing is the "listOf" property can contains values like "superman", "sv-m/ratio". And "sv-m" in sorting should come after "superman" so I want to place it ("sv-m/ratio") in the end of list. Explanation may look incomplete or confusing but this is all I know. –  Capri82 Oct 7 '14 at 20:39

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