reading-notes

Domain Modeling

Reading

• Domain Modeling

Notes

What is Domain Modeling

• Domain modeling is the process of creating a conceptual model in code for a specific problem
• The model describes the entities, attributes and behaviors, as well as constraints governing the problem domain
• Object-oriented models store data in properties and encapsulate behaviors in methods
• Tips for building domain models:
  • When modeling a single entity that’ll have many instances, build self-contained objects with the same attributes and behaviors.
  • Model its attributes with a constructor function that defines and initializes properties.
  • Model its behaviors with small methods that focus on doing one job well.
  • Create instances using the new keyword followed by a call to a constructor function.
  • Store the newly created object in a variable so you can access its properties and methods from outside.
  • Use the this variable within methods so you can access the object’s properties and methods from inside.

Constructors

• A constructor is a function that defines and initializes properties
  • Can basically construct an object consisting of similarly defined objects for later use by the program

• Example:

  var EpicFailVideo = function(epicRating, hasAnimals) { //Constructor function
    this.epicRating = epicRating; // Property 1
    this.hasAnimals = hasAnimals; // Property 2
  }
  
  var parkourFail = new EpicFailVideo(7, false); // Instantiates a new object parkourFail(7,false)
  var corgiFail = new EpicFailVideo(4, true); // Instantiates a new object corgiFail(4,true)
  
  console.log(parkourFail);
  console.log(corgiFail);
  

• This is object-oriented programming in JavaScript at its most fundamental level:
  • The new keyword instantiates (i.e. creates) an object.
  • The constructor function initializes properties inside that object using the this variable.
  • The object is stored in a variable for later use.