How to increment an object property value if it exists, else set the initial value?

Question

How might I add check to see if a key already exists, and if does, increment the value, and if it doesn\'t exist, then set the initial value?

Something like this pseudo-

Answer 1

You can do this in a lot of ways. In general if you want to know if an Object has a key you use the in modifier with the key name. This looks like:

var key = "key name";
var dict = {};
var hasKey = (key in dict);

Though you can check if a value is set by simply testing if it is undefined. This being that in JavaScript if you don't have a value initialized and send it through an if statement it will act as a false. Which looks like:

var dict = {};
if(dict[key]) {
   print("key: " + dict[key]);
} else {
   print("Missing key");
}