I would like to understand how the built-in function property works. What confuses me is that property can also be used as a decorator, but it only takes arguments when used as a built-in function ... A property should always encapsulate one or more fields, and should never do any heavy lifting or validation.
If you need a property such a UserName or Password to have validation, change their type from strings to Value Objects. There is an unspoken contract between a class-creator and the consumer. Descriptors like property need to be in the type's dictionary to work their magic. So those in a class definition primarily affect the behaviour of instances of the class, with minimal effect on the behaviour of the class itself (since the class is the type of the instances).
property incorporation, For instance in this article I read this (.. class attribute (or class property, field, or data member) I have seen rather well cut out questions that show that there is a difference between class property and class field for instance What is the difference between a Field and a Property in C#? When accessing a property, the "dot" syntax (images.main) supposes, I think, that it already exists. I had such problems without Typescript, in "vanilla" Javascript, where I tried to access data as: return json.property[0].index where index was a variable. But it interpreted index, resulting in a: cannot find property "index" of json.property[0] 2 In str's answer, value 'undefined' will be returned instead of the set default value if the property is undefined.
property incorporation, This sometimes can cause bugs. The following will make sure the defaultVal will always be returned when either the property or the object is undefined. In my situation I had my property auto initialize a command in a ViewModel for a View. I changed the property to use expression bodied initializer and the command CanExecute stopped working. Here's what it looked like and here's what was happening. A given property name can be absent on an object (producing the value undefined when read), present on the object itself with the value undefined, present on the object’s prototype with the value undefined, or present on either of those with a non- undefined value.
'key' in obj will tell you whether a key is anywhere on an object’s ...
