compactor.js

'use strict';

// linting rules prevent modifying Object directly
var extend = Object;

extend.compact = function (obj) {
    var self = this;

    function compactArray(array) {
        return array.filter(function (value) {
            return value;
        });
    }

    if (Array.isArray(obj)) {
        obj = compactArray(obj);
    }
    for (var key in obj) {
        if (typeof obj[key] == 'object') {
            if (Array.isArray(obj[key])) {
                obj[key] = compactArray(obj[key]);
            }
            self.compact(obj[key]);
        }
        if (!obj[key]) {
            delete obj[key];
        }
    }
    if (obj) {
        return obj;
    }
}

// tests
var obj = {
    true: {
        string: 'string',
        number: 1,
        boolean: true,
        object: {},
        array: [{
            false: {
                string: '1',
                number: 0,
                boolean: false,
                null: null
            }
        }, 1, 0, true]
    },
    false: {
        string: '',
        number: 0,
        boolean: false,
        null: null
    },
    one: 0
};

var array = [1, 2, 3, 0, {
    string: '',
    number: 0,
    boolean: false,
    null: null
}];

Object.compact(obj);
Object.compact(array);

console.log(obj);
console.log(array);