gistfile1.txt

var people = [
    {
        "age": 3,
        "name": "Rob"
    }, {
        "age": 5,
        "name": "Tylor"
    },{
        "age": 4,
        "name": "Eric"
    }
];

people.sort(function(a, b) {
    return parseFloat(a.age) - parseFloat(b.age);
});

console.log("people",people);