A Query Language for JavaScript Objects

HEY GIRL, AS A JAVASCRIPT PROGRAMMER I COULDN

Let's say that we have a JavaScript object like so:

var person = {  
    name: {
        first: 'Kanye',
        last: 'West',
    },
    kids: [
        {
            name: {
                first: 'North',
                last: 'West',
            },
            favoriteThings: [
                "Gucci",
                "Ice"
            ],
        },
        {
            name: {
                first: 'South',
                last: 'West',
            },
            favoriteThings: [
                "Pizza",
                "Balloons"
            ],
        }
    ],
    spouse: {
        name: {
            first: 'Kim',
            last: 'Kardashian',
        },
    },
}

I wrote a simple function that will allow you to write a query against this object and return what it finds. It always returns an array, even if it only has one thing in it.

You call it like this:

var firstName = select(person, 'name.first');  
// ['Kanye']

var spouseName = select(person, 'spouse.name');  
// [{ first: 'Kim', last: 'Kardashian' }]

var kidFirstNames = select(x, 'kids.name.first');  
// ['North', 'South']

var spouseFirstLast = select(x, 'spouse.name.first spouse.name.last');  
// ['Kim', 'Kardashian']

var kidFirstNamesLastNames = select(x, 'kids.name.first   kids.name.last');  
// ['North', 'South', 'West', 'West']

var kidFavoriteThings = select(x, 'kids.favoriteThings');  
// [ ['Gucci', 'Ice'], ['Pizza', 'Balloons'] ]

Let me know what you think of it. It is definitely not the first of it's kind, even for JavaScript, but it's a super simple implementation. It has two small functions select and isArray which is used in select.

You can see the code below and do what you like with it. I included an MIT license statement with it.
Have fun.

function isArray(obj) {  
    return toString.call(obj) === '[object Array]';
}

function select(obj, query, result) {  
    var parts, ptr, term;

    try {
        if (query == null || query.trim() === '') throw 'query is required';
        if (obj == null) throw 'obj is required';

        parts = query.split(/\s+/);

        if (parts.length > 1) {
            parts.forEach(function(part) {
                result = select(obj, part, result);
            });
            return result;
        } else {
            parts = query.split('.');
        }

        if (!result) result = [];
        ptr = obj;

        while(parts.length) {
            term = parts.shift();

            ptr = ptr[term];
            if (ptr === undefined) throw '';
            if (ptr === null) return null;

            if (parts.length && isArray(ptr)) {
                ptr.forEach(function(item) {
                    result = select(item, parts.join('.'), result);
                });
                return result;
            }
        }

        result.push(ptr);

        return result;
    }
    catch (e) {
        console.log('bad query: ' + query);
    }
}

/*
The MIT License (MIT)

Copyright (c) 2015 Chris Grimes

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.  
*/

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