iterate-obj-props.js

var obj = {
	a: "a",
	b: "b",
	c: [0, 1, 2]
}

for (var key in obj) {
    if (obj.hasOwnProperty(key)) {
        console.log(key + ': ' + obj[key]);
    }
}

//ES6:
Object.keys(obj).forEach(function(key,index) {
    console.log(index + " " + key + ': ' + obj[key]);
});

//iterate-props:
function forEachProps(obj, action) {
    for (var key in obj) {
        if (obj.hasOwnProperty(key)) {
            action(obj[key]);
        }
    }
}
forEachProps({a:"a", b:"b"}, console.log)