Skip to content

another 14 solution #48

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Open
wants to merge 1 commit into
base: main
Choose a base branch
from
Open

another 14 solution #48

Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
19 changes: 15 additions & 4 deletions src/03-type-predicates-assertion-functions/14-typescripts-worst-error.solution.ts
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -15,13 +15,23 @@ interface NormalUser extends User {
role: "normal";
}

function assertUserIsAdmin(
const assertUserIsAdmin: (
user: NormalUser | AdminUser,
): asserts user is AdminUser {
) => asserts user is AdminUser = (
user: NormalUser | AdminUser,
): asserts user is AdminUser => {
if (user.role !== "admin") {
throw new Error("Not an admin user");
}
}
};

// function assertUserIsAdmin(
// user: NormalUser | AdminUser,
// ): asserts user is AdminUser {
// if (user.role !== "admin") {
// throw new Error("Not an admin user");
// }
// }

it("Should throw an error when it encounters a normal user", () => {
const user: NormalUser = {
Expand All @@ -37,7 +47,8 @@ it("Should assert that the type is an admin user after it has been validated", (
const example = (user: NormalUser | AdminUser) => {
/**
* The fix is to make assertUserIsAdmin a function,
* not an arrow function. Lord above.
* or to add the explicit type annotation back to the arrow function
* Lord above.
*/
assertUserIsAdmin(user);

Expand Down