Iterating over nested array of objects [duplicate]

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. — user663031
– user663031, Commented Nov 30, 2016 at 9:04

Nina Scholz · Accepted Answer · 2016-11-30 08:32:41Z

2

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";
});

answered Nov 30, 2016 at 8:32

Nina Scholz

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kukkuz · Accepted Answer · 2016-11-30 08:29:21Z

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);

.as-console-wrapper{top:0;max-height:100%!important;}

answered Nov 30, 2016 at 8:29

kukkuz

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4 Comments

user663031 Over a year ago

What is the point of the e.status && part?

kukkuz Over a year ago

check if status is a property of e

user663031 Over a year ago

It's not necessary. If status is not a property of e, then e.status will be undefined, which will not equate with "COMPLETED".

kukkuz Over a year ago

you are right, it has become a habbit for me to write that check :)

C14L · Accepted Answer · 2016-11-30 08:29:48Z

1

That's what JavaScript filters are for.

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

answered Nov 30, 2016 at 8:29

C14L

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