The following is understanding of the angular
this is a test
components: data, htmltemplate, logic
modules: containers of group of related components (default module of angular called app module)
work on components
steps: create component, register in module, add an element in html markup
component
if we must have a property in components, we must have html in component
selector could select element e.g.'' or attribute e.g. ‘[]’， or class e.g. '.__'
if we have selector select on attribute, we will need to have html to have any elements with attribute of such mentioned in selector, or if class we will need to have same naming in html
String interpolation: getting the string in angular in specific method
services: