Typescript error handling : https://twitter.com/housecor/status/1612222617141878784

createUser.ts

export async function createUser() {

  const {user, error} = await api.createUser();
  
  if(error) {
    throw new UserError({
      name: "CREATE_USER_ERROR",
      message: "Failed to create user",
      cause: error
    })
  }
  
}

error.ts

export class ErrorBase<T extends string> extends Error {
  name: T;
  message: string;
  cause: any;

  constructor(error: ErrorWithCause<T>) {
    super();
    this.name = error.name;
    this.message = error.message;
    this.cause = error.cause;
  }
}

interface ErrorWithCause<T> {
  name: T;
  message: string;
  cause: any;
}

class UserError extends ErrorBase<"GET_USER_ERROR" | "CREATE_USER_ERROR"> {}

front.ts

try {
  await createUser();
}
catch(e) {
  if(e instanceof UserError && e.name === "CREATE_USER_ERROR") {
    toast(e.message)
  }
}