reserved

The CandidType object reserved corresponds to the Candid type reserved, is inferred to be a TypeScript any, and will be decoded into a JavaScript null at runtime.

TypeScript or JavaScript:

import { Canister, query, reserved } from 'azle';

export default Canister({
    getReserved: query([], reserved, () => {
        return 'anything';
    }),
    printReserved: query([reserved], reserved, (reserved) => {
        console.log(typeof reserved);
        return reserved;
    })
});

Candid:

service : () -> {
    getReserved : () -> (reserved) query;
    printReserved : (reserved) -> (reserved) query;
}

dfx:

dfx canister call candid_canister printReserved '(null)'
(null : reserved)