Best practice looping through a JavaScript object

Question

I have the following JavaScript object which I need to apply parseFloat to any number value field (in order for ngTable to sort correctly).

I'm having a tough time looping through the Object to do this. I've tried a nested angular.forEach, but I have scoping issues (inner loops don't see outer variables).

What's the best manner to approach this?

The Object names (i.e: Person and PersonDetails) are dynamic. :/

My object:

{
    "data": [
        {
            "Person": {
                "id" : "1",
                "age": "23",
                "days": "5",
                "first_name": "Joe",
                "last_name": "Smith",
            },
            "PersonDetails": {
                "id": "4",
                "name": "Cousin",
                "oldest: "2",
            }
        },
        {
            "Person": {
                "id" : "2",
                "age": "18",
                "days": "3",
                "first_name": "John",
                "last_name": "Doe",
            },
            "PersonDetails": {
                "id": "4",
                "name": "Second Cousin",
                "oldest: "3",
            }
        }
        ...
        ...
    ]
};

The duplicate I posted covers iterating both over objects and arrays, despite its name. — Jeremy J Starcher, Apr 13 '14 at 00:46

score 16 · Accepted Answer · edited Sep 04 '19 at 16:28

You can do a test like this:

function representsNumber(str) {
    return str === (+str).toString();
}

// E.g. usage
representsNumber('a'); // false
representsNumber([]); // false
representsNumber(1); // false (it IS a number)
representsNumber('1.5'); // true
representsNumber('-5.1'); // true
representsNumber('NaN'); // true

And recurse over all your nodes. Overkill example:

function seeker(o, test, _true, _false) {
    _true || (_true = function (e) {return e;});
    _false || (_false = function (e) {return e;});
    function recursor(o) {
        var k;
        if (o instanceof Array)
            for (k = 0; k < o.length; ++k) // Iterate over an array
                if (typeof o[k] !== 'object')
                    o[k] = test(o[k]) ? _true(o[k]) : _false(o[k]);
                else
                    recursor(o[k]);
        else
            for (k in o) // Iterate over an object
                if (typeof o[k] !== 'object')
                    o[k] = test(o[k]) ? _true(o[k]) : _false(o[k]);
                else
                    recursor(o[k]);
    }
    if (typeof o === "object") 
        return recursor(o), o;
    else 
        return test(o) ? _true(o) : _false(o); // Not an object, just transform
}

// Sample usage
seeker({foo: [{bar: "20"}]}, representsNumber, parseFloat);
// {foo: [{bar: 20}]}

Best practice looping through a JavaScript object

1 Answers1