d) Not declaring types, he means not using types for declaration
- In languages, like C and Java you must give variables a type
What about :
var something = somethingElse();
Sometimes you're dealing with some kind of method that uses some type you're not really familiar with other than you can access a few methods attached to the returned data to get what you need.
You're technically not giving it a type, your'e just letting it figure it out via var.