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 use the ternary operator (?:) like this:

dictionary[key] ? 
    dictionary[key].value += 1 : 
    dictionary[key] = {value: 1};