adding to json property that may or may not exist yet

Question

let say I want to do this:

  var dashboard = {};
  var page = \"index\";

  $(\'.check\').click(function(){ 
    $(thi         


        

Answer 1

I don't think there's a good builtin way to do this, but you could always abstract it with a function.

function getProperty(obj,prop){
    if( typeof( obj[prop] ) == 'undefined' ){
        obj[prop] = {};
    }
    return obj[prop];
}

Then you use

getProperty(dashboard,'pages')['pagename']

or

getProperty(getProperty(dashboard,'pages'),'pagename');

As mentioned, $.extend will make this less burdensome.

Answer 2

Well I guess you need this:

var dashBoard = new Array();
if(!dashboard['page123']) {
    dashBoard.push('page123');
} else {
...do what you want
}

Seems you are dealing with XML.

Answer 3

If you use underscore >= 1.9.0, you can use property and propertyOf:

d={a: {b: "c"}}
_.property(["a", "b", "c", "e"])(d)   // undefined
_.property(["a", "b"])(d)             // "c"
_.propertyOf(d)(["a", "b", "c", "e"]) // undefined
_.propertyOf(d)(["a", "b"])           // "c"

Answer 4

var foo = dashboard['pages'] || {};
foo['pagename'] = 'your thing here';
dashboard['pages'] = foo;

Explaining: the first line will check if the first value is null, undefined or... false (don't think this is a problem here): if it is, create a new object, if it is not, will use it.

Answer 5

I would do it with the ternary operator:

dashboard['pages'][page] = dashboard['pages'][page] ? dashboard['pages'][page] : {};

That will do the trick no matter if it's set/null or whatever.

Answer 6

The best solution for my case was to do a Object prototype

 /**
 * OBJECT GET
 * Used to get an object property securely
 * @param object
 * @param property
 * @returns {*}
 */
Object.get = function(object, property) {
    var properties = property.split('.');
    for (var i = 0; i < properties.length; i++) {
        if (object && object[properties[i]]) {
            object = object[properties[i]];
        }
        else {
            return null;
        }
    }
    return object;
};

And then you can get your property like this

var object = { step1: { step2: { step3: ['value1', 'value2'] }}}
Object.get(object, 'step1.step2.step3'); // ['value1', 'value2']
Object.get(object, 'step1.step2.step3.0'); // 'value1'
Object.get(object, 'step1.step2.step3.step4'); // null

Hope it helps :)