delete operatorThe delete operator is a unary operator that removes a named property from an
object. If you set a property to undefined, the in operator will still
return true (as the object still has the property). However, if you delete
it, the in operator will return false.
Besides the very popular push and pop methods, array also have the shift
and unshift methods, that pop the first element out and insert an element
into the first position, respectively.
In JavaScript, you are allowed to pass a function more (or fewer) arguments
than the number of declared parameters. Inside a function, an arguments
object is available. As the name indicated, it is a representation of the
arguments passed to the function. Although it looks like an array, it is not
one, so you cannot call slice on it, for instance.