Attribute and subscript

1. Storage attributes are divided into constant attributes (let) and variable attributes (VAR)

2, using lazy definition delay load, as the name implies in the first access will be loaded, if not access, never back to create, so reduce memory consumption.

3. The attribute watcher Willset called Didset after the new value is set before setting a new value.

4, calculate the property, provide getter (accessor) setter (set accessor)

5 static property.

6, arrays and dictionaries can be accessed using subscript, for example: Var status:string[]=["1", "2", "2"] status[0]= "2"

Attribute and subscript