Given an array of JSON objects, how can I get JSON object X based on a nested value?

Question

I am using google maps geocoding api to get the following JSON object, based on an address:

{
    "results":[
        {
            "address_components":[
                {
                    "long_name":"643",
                    "short_name":"643",
                    "types":[
                        "subpremise"
                    ]
                },
                {
                    "long_name":"900",
                    "short_name":"900",
                    "types":[
                        "street_number"
                    ]
                },
                {
                    "long_name":"Folsom Street",
                    "short_name":"Folsom St",
                    "types":[
                        "route"
                    ]
                },
                {
                    "long_name":"South of Market",
                    "short_name":"South of Market",
                    "types":[
                        "neighborhood",
                        "political"
                    ]
                },
                {
                    "long_name":"San Francisco",
                    "short_name":"SF",
                    "types":[
                        "locality",
                        "political"
                    ]
                },
                {
                    "long_name":"San Francisco County",
                    "short_name":"San Francisco County",
                    "types":[
                        "administrative_area_level_2",
                        "political"
                    ]
                },
                {
                    "long_name":"California",
                    "short_name":"CA",
                    "types":[
                        "administrative_area_level_1",
                        "political"
                    ]
                },
                {
                    "long_name":"United States",
                    "short_name":"US",
                    "types":[
                        "country",
                        "political"
                    ]
                },
                {
                    "long_name":"94107",
                    "short_name":"94107",
                    "types":[
                        "postal_code"
                    ]
                },
                {
                    "long_name":"1007",
                    "short_name":"1007",
                    "types":[
                        "postal_code_suffix"
                    ]
                }
            ]
        }
    ]
}

Question

How can I get the long_name and short_name of an object in the address_components array based on a particular type?

Example

I want to get the long_name and short_name of those objects that have "locality" in their types array.

Context

I'm using this information to build an "apartment finder" application using node.js, express, and mongodb.

Considerations

I've read that underscore library is good for this.

Edit: My Thoughts

So, I have an idea how to search through the address_components array. (I can access it by results[0]), and I believe I can access types array by dot notation, but I want to search through all the types arrays of each object and return when I find an object with, let's say, types containing 'location'. How can I do this?

I'm not that well experienced parsing/looping JSON. I am learning. Any help is greatly appreciated. Thank you!

Answer 1

You can use a nested .filter to get the objects containing that, combined with .map to create an array of matching objects:

var objectsContainingConditions = data.results[0].address_components.filter(function(item) {
    return item.types.filter(function(addressType) {
        return addressType == "locality";
    }).length > 0;
}).map(function(item) {
    return {
        long: item.long_name,
        short: item.short_name
    }
});

Put this into a function and pass the type if you want to reuse it:

function queryGoogleComponentsByType(type, components) {
    return components.filter(function(item) {
        return item.types.filter(function(addressType) {
            return addressType == type;
        }).length > 0;
    }).map(function(item) {
        return {
            long: item.long_name,
            short: item.short_name
        }
    });
}

var results = queryGoogleComponentsByType("locality", data.results[0].address_components);

Demo: http://jsfiddle.net/upzjth30/

Answer 2

If you want to use underscore, here is a solution that will show you how to use its primitives to achieve the result you are looking for

This will look for the first component that has a type of 'locality'

var result = _.chain(json.results)
              .pluck('address_components')
              .flatten()
              .find(function(component) {
                return  _.contains(component.types, 'locality');
              })
              .pick('long_name', 'short_name')
              .value()

Demo: https://jsfiddle.net/x9520bkx/

Answer 3

for (var i = 0; i < data.results[0].address_components.length; i++) {
    alert(data.results[0].address_components[i].short_name);
}