Iterating over nested array of objects

Question

I'm trying to iterate over this object containing a array of quests-objects. How would i be able to iterate over each key value pairs to for example return all quests which have the status "completed".

{
    "quests": [
        {
            "title": "A Rum Deal",
            "status": "COMPLETED",
            "difficulty": 2,
            "members": true,
            "questPoints": 2,
            "userEligible": true
        }
    ],
    "loggedIn": false
}

I don't think you want to "iterate over each key value pairs". You want to iterate over the **elements** in the array. Key/value pairs are a feature of objects; elements are a feature of arrays. By the way, even if you did not know the word "filter", a Google search for `find matching object array javascript property` would have turned up an answer right away. — , Nov 30 '16 at 09:04

score 2 · Accepted Answer · answered Nov 30 '16 at 08:32

For iterating you could use Array#forEach

object.quests.forEach(function (a) {
    if (a.status === "COMPLETED") {
        // do something with the data
    }
});

For returning a selection with completed task, you could use Array#filter

var completed = object.quests.filter(function (a) {
    return a.status === "COMPLETED";
});

score 1 · Answer 2 · answered Nov 30 '16 at 08:29

1

Use Array.prototype.filter to filter out the elements which have 'completed' status - see demo below:

var array={"quests":[{"title":"A Rum Deal","status":"COMPLETED","difficulty":2,"members":0,"questPoints":2,"userEligible":0},{"title":"A Rum Deal","status":"NOT_COMPLETED","difficulty":2,"members":0,"questPoints":2,"userEligible":0}],"loggedIn":1};

var result = array.quests.filter(function(e){
   return e.status && e.status === "COMPLETED";
});

console.log(result);

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answered Nov 30 '16 at 08:29

kukkuz

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What is the point of the `e.status &&` part? – Nov 30 '16 at 09:01
check if `status` is a property of `e` – kukkuz Nov 30 '16 at 09:03
1

It's not necessary. If `status` is not a property of `e`, then `e.status` will be undefined, which will not equate with `"COMPLETED"`. – Nov 30 '16 at 09:03
you are right, it has become a habbit for me to write that check :) – kukkuz Nov 30 '16 at 09:04

score 1 · Answer 3 · answered Nov 30 '16 at 08:29

1

That's what JavaScript filters are for.

myObj.quests.filter(item => item.status === 'COMPLETED');

answered Nov 30 '16 at 08:29

C14L

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Iterating over nested array of objects

3 Answers3