**Type aliases** let you create new names for types. This makes your code easier to read and reuse.


```ts
// Type alias
type Person = {
name:string
age:number
}

// Use type alias in the annotation
const greetPerson = (person: Person) => {
    return `Hello, ${person.name}! You are ${person.age} years old.`;
}
```

**Union Types** allow us to give a value a few different possible types. We can create a union type by using the single | (pipe character) to separate the types we want to include

```ts
function formatInput(input: string | number) {
  if (typeof input === "number") {
    return input.toFixed(2);
  } else {
    return input.toUpperCase();
  }
}
```
**Intersection Types** combine multiple types into one that has all properties of the intersected types.

```ts

type Circle ={
radius: number;
}

type Colored = {
color: string;
}

type ColoredCircle = Circle & Colored;

const circleExample: ColoredCircle = {
color: "red",
radius:  5
}

```

A **literal type** allows a variable to be assigned **only one specific value**.  A **union of literal types** is a type that allows a value to be **one of several exact, predefined values**, enhancing type safety by restricting inputs to a specific set of possibilities.

```ts

const getTrafficLight = (trafficLight: "red" | "yellow" | "green") => {
     return `The traffic light is : ${trafficLight}`
}

getTrafficLight("red");     //  Works
getTrafficLight("yellow");  //  Works
getTrafficLight("green");   //  Works

getTrafficLight("blue");    //  Error

```


Type Aliases, Union, Literal, and Intersection Types in TypeScript

Define custom types using type aliases, combine types with unions, and merge types with intersections to write flexible, reusable TypeScript code.

Typescript advanced types

Type Aliases, Union, Literal, and Intersection Types in TypeScript