Type Aliases and Literal Unions

Type aliases can name a set of literal values and make branch choices explicit.

aliases.ts

type Status = "draft" | "review" | "published";

function statusLabel(status: Status): string {
    if (status === "published") {
        return "visible";
    }
    if (status === "review") {
        return "checking";
    }
    return "hidden";
}

const status: Status = ;
const label: string = statusLabel(status);

console.log(`${status}=${label}`);

type Status = "draft" | "review" | "published";

function statusLabel(status: Status): string {
    if (status === "published") {
        return "visible";
    }
    if (status === "review") {
        return "checking";
    }
    return "hidden";
}

const status: Status = ;
const label: string = statusLabel(status);

console.log(`${status}=${label}`);

type Status = "draft" | "review" | "published";

function statusLabel(status: Status): string {
    if (status === "published") {
        return "visible";
    }
    if (status === "review") {
        return "checking";
    }
    return "hidden";
}

const status: Status = ;
const label: string = statusLabel(status);

console.log(`${status}=${label}`);

literal union A literal union type allows only specific values such as `"draft"` or `"published"`.