TypeScript Mastering

1. JavaScript vs TypeScript Types

	Javascript	Typescript
1	undefined	undefined
2	boolean	boolean
3	number	number
4	string	string
5	bigint	number
6	symbol	symbol
7	null	null
8	object	object
9	function	function
10	-	any
11	-	union
12	-	intersection
13	-	enum
14	-	void
15	-	advance type

Notes :

• 1-6 are Primitive Data Types
• All primitives are immutable. A primitive is not an object and has no methods of its own.
• Null is special primitive
• All types in TypeScript are subtypes of a single top type called the Any type.

Exercises :

• Evaluate all JavaScript Types
• undefined vs null vs not defined
• Cons & Pros Dynamic Type

2. Typescript Types

How to declare typescript type :

• Type inference ( implicit ) let ti = "hello"
• Type annotations ( explicit ) let ta:string = "hello ts"

Exercises :

• Convert all JavaScript Types to TypeScript
• Function Type
• Union Type |
• Type Aliases
• Setup Environtment ( eslint, prettier )

3. Array & Tuples

Tuples is an array with fixed size and known data types.

There are few ways to declare an array:

1. Using Type Inference let list = [1, 2, 3, 4];
2. Using square brackets. elementType[] let fruits: string[] = ['Apple', 'Orange', 'Banana'];
3. Using a generic array type. Array<elementType> let fruits: Array<string> = ['Apple', 'Orange', 'Banana'];

Exercises :

• Array of Number
• Array of String
• Array with Union
• Tuple
• Array of Object
• Array multidimensional
• Destructuring

4. Object

Object is a type that represents the non-primitive type, i.e. anything that is not number, string, boolean, bigint, symbol, null, or undefined

Exercises :

• Object Literal
• Nested Object
• Nested, Object of Array
• Nested, Object of Object ( Dynamic Properties)
• Destructuring
• Utility Types ( ReadOnly, Record )

5. Functions

Functions are the building blocks of readable, maintainable, and reusable code. A function is a set of statements to perform a specific task. Functions organize the program into logical blocks of code.

Exercises :

• function basic : declaration,expression, arrow
• optional & default parameters
• rest parameter
• conditional type with union, generic, overloads

6. Classes

• class basic : constructor, properties, method
• access modifiers (private, public, protected)
• inheritance / sub-class
• static member
• abstract classes

access modifier	class	sub-class	instance
public	✅	✅	✅
protected	✅	✅	❌
private	✅	❌	❌