超越枚举：TypeScript Const 断言与联合类型

            enum DirectionNumeric {
  Up,
  Down,
  Left,
  Right
}

let myDirection: DirectionNumeric = DirectionNumeric.Up;
console.log(myDirection); // Output: 0

            

              
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            enum StatusCode {
  Success = 200,
  NotFound = 404,
  InternalError = 500
}

let responseStatus: StatusCode = StatusCode.Success;
console.log(responseStatus); // Output: 200

            

              
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            enum ColorString {
  Red = "RED",
  Green = "GREEN",
  Blue = "BLUE"
}

let favoriteColor: ColorString = ColorString.Blue;
console.log(favoriteColor); // Output: "BLUE"

            

              
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            enum Status {
  Pending = "PENDING",
  Processing = "PROCESSING",
  Completed = "COMPLETED"
}

            

              
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            var Status;
(function (Status) {
    Status["Pending"] = "PENDING";
    Status["Processing"] = "PROCESSING";
    Status["Completed"] = "COMPLETED";
})(Status || (Status = {}));

            

              
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            const statusArray = ["PENDING", "PROCESSING", "COMPLETED"] as const;

type StatusType = typeof statusArray[number];

let currentStatus: StatusType = "PROCESSING";
// currentStatus = "FAILED"; // Error: Type '"FAILED"' is not assignable to type 'StatusType'.

function processStatus(status: StatusType) {
  console.log(`Processing status: ${status}`);
}

processStatus("COMPLETED");

            

              
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            const userRoles = {
  Admin: "ADMIN",
  Editor: "EDITOR",
  Viewer: "VIEWER"
} as const;

type UserRole = typeof userRoles[keyof typeof userRoles];

let currentUserRole: UserRole = "EDITOR";
// currentUserRole = "GUEST"; // Error: Type '"GUEST"' is not assignable to type 'UserRole'.

function displayRole(role: UserRole) {
  console.log(`User role is: ${role}`);
}

displayRole(userRoles.Admin); // Valid
displayRole("EDITOR"); // Valid

            

              
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            var userRoles = {
    Admin: "ADMIN",
    Editor: "EDITOR",
    Viewer: "VIEWER"
};

            

              
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            type TrafficLightColor = "RED" | "YELLOW" | "GREEN";

let currentLight: TrafficLightColor = "YELLOW";
// currentLight = "BLUE"; // Error: Type '"BLUE"' is not assignable to type 'TrafficLightColor'.

function changeLight(color: TrafficLightColor) {
  console.log(`Changing light to: ${color}`);
}

changeLight("RED");
// changeLight("REDDY"); // Error

            

              
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            type HttpStatusCode = 200 | 400 | 404 | 500;

let responseCode: HttpStatusCode = 404;
// responseCode = 201; // Error: Type '201' is not assignable to type 'HttpStatusCode'.

function handleResponse(code: HttpStatusCode) {
  if (code === 200) {
    console.log("Success!");
  } else {
    console.log(`Error code: ${code}`);
  }
}

handleResponse(500);

            

              
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            enum ApiStatus {
  Success = "SUCCESS",
  Error = "ERROR",
  Pending = "PENDING"
}

function handleApiResponse(status: ApiStatus) {
  // ... logic ...
}

            

              
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const apiStatusCodes = {
  SUCCESS: "SUCCESS",
  ERROR: "ERROR",
  PENDING: "PENDING"
} as const;

type ApiStatus = typeof apiStatusCodes[keyof typeof apiStatusCodes];

function handleApiResponse(status: ApiStatus) {
  // ... logic ...
}

            

              
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type ApiStatus = "SUCCESS" | "ERROR" | "PENDING";

function handleApiResponse(status: ApiStatus) {
  // ... logic ...
}

            

              
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enum UserRoleEnum {
  Admin = "ADMIN",
  Moderator = "MODERATOR",
  User = "USER"
}

function getUserPermissions(role: UserRoleEnum) {
  // ... logic ...
}

            

              
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const userRolesObject = {
  Admin: "ADMIN",
  Moderator: "MODERATOR",
  User: "USER"
} as const;

type UserRole = typeof userRolesObject[keyof typeof userRolesObject];

function getUserPermissions(role: UserRole) {
  // ... logic ...
}

            

              
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type UserRole = "ADMIN" | "MODERATOR" | "USER";

function getUserPermissions(role: UserRole) {
  // ... logic ...
}

            

              
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enum Theme {
  Light = "light",
  Dark = "dark",
  System = "system"
}

interface AppConfig {
  theme: Theme;
  // ... other config options ...
}

            

              
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const themes = {
  Light: "light",
  Dark: "dark",
  System: "system"
} as const;

type Theme = typeof themes[keyof typeof themes];

interface AppConfig {
  theme: Theme;
  // ... other config options ...
}

            

              
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type Theme = "light" | "dark" | "system";

interface AppConfig {
  theme: Theme;
  // ... other config options ...
}

            

              
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