TypeScript Literal Types

Literal types mean: value must be exact.

  ## Example
  
  ```ts
  let status: "loading" | "success" | "error";
  
  status = "loading"; // ok
  // status = "done"; ❌ error
  ```
  
  ## Why useful?
  Prevents invalid states.
  
  ```ts
  type Role = "admin" | "user";
  
  function setRole(role: Role) {
    console.log(role);
  }
  ```
  
  ## With numbers
  
  ```ts
  type Dice = 1 | 2 | 3 | 4 | 5 | 6;
  ```
  
  ## Graph
  
  ```mermaid
  flowchart LR
    A[status] --> B[loading]
    A --> C[success]
    A --> D[error]
  ```
  
  ## Remember
  - Literal types lock values
  - Great for states and configs