- Nested list : can put a second list inside an
- element to create a sub�list or nested list.
- Arrays are especially helpful when you do not know how many items a list will contain.
- The values in the array do not need to be the same data type.
- Each item in an array is automatically given a number called an index.
- null and undefined are both falsy, they are not equal to anything other than themselves.
- NaN is considered falsy, it is not equivalent to anything; it is not even equivalent to itself.