AhmedElgaidi / typescript-training-3

TypeScript with iLECHUNO:

1) Any statically typed language follows one of two ways to assing data types to values

1) Implicit Way:

• It's called "Type annotation"
• It's When telling typescript what exactly data type to use with variables!!

let userName: string = "Ahmed Elgaidi";
const age: number = 23;
let skills: string[] = ["web development", "mobile development"];

2) Explicit Way:

• It's called "Type Inference"
• It's like an auto mode for use, the typscript checks the given value and based on it It'll assume that it's type of ex. string

let userName = "Ahmed";

under the hoode it would be "Type Annotation" for use.

2) Data Types:

1) Primitive Data Types:

• string
• number
• boolean
• undefined
• null
• void

2) Reference Data Types:

• function
• class
• object
• array

3) Data type annotation:

Check the playground code to see examples

4) Interfacs:

• It's like a schema you can use it in different places!

5) OOP:

• Class
• Inheritance (Inherit properites an method from another class)
• Passing args into constructor (Cleaner way of assinging a dynamic value to class intances)
• Modifiers
  • public: You can access anywhere (current class, child class, instances), anytime
  • private: you can only access within the same class
  • protected: you can access only from same class and child classes
• Accessors
  • get:
    • It makes you access a private (propery/ method) from public
    • Benefit: you only can access it - No modifications!!!
  • set:
    • It makes you modify a private property
    • Benefit: You only can change it just values previously determined!!!
• readonly: access only from outside (the same concept of get accessor)
• static: you add this to whatever property/ method you want and you can get access to it without creating a new instances of this class!! (Really helpfull)
• static: to accesss a property/ method of a class without creating an instance of it.
• abstract:
  • It's just a blue print for being extended by other classes
  • You can't create instances of this class!!

6) Modules& namespaces:

• Modules: (import & export)
• namespace: It's actually an object where you put your variables/ functions that you want to export and import them somewhere using the object notation.

7) Generics:

The idea is to make code generic to be reusable as much as possible!

• Generic functions
• Generic classes
• generic interfaces Used especially when passing certain object as a parameter to a function