TypeScript14 min readTypeScript Literal Types
Learn literal types to restrict values to exact strings or numbers, useful for configs and API states.
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