Testing Objects in JS Arrays

Question

Testing Objects in JS Arrays

I have an array of objects returned after an API request. It takes the form:

[{
    id: 12,
    slug: '050e8e8db93ae08ed46cd57017ef9617',
    name: 'Test Badge'
}, {
    id: 13,
    slug: '78ed09b1f2aae29ab30915ac9f167bfa',
    name: 'Test Badge'
}]

I need to check the value: x

on the : key slug

, but my array of objects is hundreds of objects. Is there a way to check the value without going through all the objects manually?

+3

json javascript arrays

Peachey_A 12 jan. 15 at 17:08

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3 answers

Question: is a filter or test array needed for the value? If a test, then it is better to use the some () function.

Update: . According to jsPerf http://jsperf.com/json-stringify-vs-array-loop some () is 800x faster, then filter () and 5000 then JSON.stringify.

    var data = [{
        id: 12,
        slug: '050e8e8db93ae08ed46cd57017ef9617',
        name: 'Test Badge'
    }, {
        id: 13,
        slug: '78ed09b1f2aae29ab30915ac9f167bfa',
        name: 'Test Badge'
    }];

    function test(x) {
        return data.some(function(d){return x==d.slug});
    };

    console.log(test('78ed09b1f2aae29ab30915ac9f167bfa'))

Run code

0

agershun 12 jan. 15 at 17:14

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Another option is "no repeating" (this is possible because your key is very specific), but this is slower since JSON.stringify is slow:

function test(x) {
    return JSON.stringify(data).indeOf(x) > -1;
}

0

agershun 12 jan. 15 at 17:19

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Fuzzyma · Accepted Answer · 2015-01-12T17:13:49+0000

Well, somehow you need hinges. But at least JavaScript does the job for you:

var arr = [
    {
        id: 12,
        slug: '050e8e8db93ae08ed46cd57017ef9617',
        name: 'Test Badge'
    },
    {
        id: 13,
        slug: '78ed09b1f2aae29ab30915ac9f167bfa',
        name: 'Test Badge'
    }
];

var arrWithValue = arr.filter(function(el){ return el.slug === value; });

arrWithValue

contains only the elements of the array with the correct value.

When you have to access this data very often, it would be better to loop once and store each object using slug

as key

.

var sortedObj = {};
for(var i = 0, len = arr.length; i < len; ++i){
    sortedObj[arr[i].slug] = arr[i];
}

// access the object with sortedObj['someSlug']

Testing Objects in JS Arrays

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