Javascript object, access related keys

Question

I have the following Javascript object:

var icecreams = [{
    name: 'vanilla',
    price: 10,
    rating: 3
}, {
    name: 'chocolate',
    price: 4,
    rating: 8
}, {
    name: 'banana',
    price: 1,
    rating: 1
}, {
    name: 'greentea',
    price: 5,
    rating: 7
}, {
    name: 'moosetracks',
    price: 6,
    rating: 2
}, ];

I need to access the "related properties" (not sure of the exact terminology) in each section of the object. For example, if I am given the name "vanilla," I need to access a "price" of 10 and "rating" of 3. Is there a way to do this without changing the object's structure? Possibly using this?

So you need to loop over the array. Look at the object, see if it matches, if it does, you have the object you want. — epascarello
– epascarello, Commented Feb 10, 2016 at 18:41

Satpal · Accepted Answer · 2016-02-10 18:41:37Z

5

You can use Array.prototype.filter()

The filter() method creates a new array with all elements that pass the test implemented by the provided function.

var vanilla = icecreams.filter(function(o){
    return o.name === 'vanilla'
});
//As filter return's an array you need to use index thus [0] to access first element of array
console.log(vanilla[0].price);
console.log(vanilla[0].rating);

answered Feb 10, 2016 at 18:41

Satpal

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2 Comments

Przemek Over a year ago

vanilla is an array not object. it works but like that: vanilla[0].price

Satpal Over a year ago

@Przemek, thats what I have used

madox2 · Accepted Answer · 2016-02-10 19:09:47Z

4

In ECMAScript 2015 you can find object in your array like this:

var vanilla = icecreams.find(o => o.name === 'vanilla')
console.log(vanilla.price);
console.log(vanilla.rating);

ES5 analogy:

var vanilla = icecreams.reduce(function(r, o) {
    return r || (o.name === 'vanilla' ? o : undefined);
}, undefined);
console.log(vanilla.price);
console.log(vanilla.rating);

edited Feb 10, 2016 at 19:09

answered Feb 10, 2016 at 18:39

madox2

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1 Comment

Wiktor Zychla Over a year ago

The es5 version needs a fix for vanilla.

rrk · Accepted Answer · 2016-02-10 18:45:29Z

0

var icecreams = [ {name: 'vanilla', price: 10, rating: 3}, {name: 'chocolate', price: 4, rating: 8}, {name: 'banana', price: 1, rating: 1}, {name: 'greentea', price: 5, rating: 7}, {name: 'moosetracks', price: 6, rating: 2}, ];
var found = {};

for(i in icecreams){
      if(icecreams[i].name == 'vanilla'){
             found = icecreams[i];
             break;
      }
}
console.log('Price: ' + found.price);
console.log('Price: ' + found.rating);

answered Feb 10, 2016 at 18:45

rrk

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Comments

Ron Sims II · Accepted Answer · 2016-02-10 18:59:58Z

0

if you have control over the structure of the variable icecream, I'd uses an oject instead of an array to hold the flavors. This makes it simple to access the values by name.

var icecream = {
    vanilla: {price: 10, taring: 3},
    banana: {price: 1, taring: 1},
    greentea: {price: 5, taring: 7},
    moosetracks: {price: 6, taring: 2}
};

Or I'd probably adapt them if they came via AJAX (or another dynamic source):

//Assume icecream follows your original structure.
function tranformFlavors(flavors) {
    var flavorObj = {};
    flavors.forEach(item){
        flavorObj[item.name] = item;
        delete flavorObj[item.name].name;
    }
    return flavorObj;
}

icecream = transformFlavors(icecream);

answered Feb 10, 2016 at 18:59

Ron Sims II

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Comments

Stefan Yohansson · Accepted Answer · 2016-02-10 18:41:41Z

-1

If you're using ES5, you can use underscore or lodash for this.

http://underscorejs.org/#find or http://underscorejs.org/#filter or http://underscorejs.org/#where or http://underscorejs.org/#findWhere

answered Feb 10, 2016 at 18:41

Stefan Yohansson

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