Derived Objects
Derived objects enable deterministic IDs for objects, enabling offline derivation of object IDs. Click here to read more.
To derive an object ID, you can import deriveObjectID function exposed from utils.
import { deriveObjectID } from '@mysten/sui/utils';To derive any object, you need to have its parent's ID (the object from which it was derived), and the key used to generate it.
It is recommended to verify the on-chain derived_object::derive_address match your off-chain
calculation (at least once when implementing offline calculations), especially for critical cases
like transferring assets.
Deriving using primitive keys
To derive the IDs using primitive types, you can use the built-in types like this, assuming you have
a parent object with ID 0xc0ffee.
// Example 1: On-chain derivation for `0xc0ffee + vector<u8>([0,1,2])
deriveObjectID('0xc0ffee', 'vector<u8>', bcs.vector(bcs.u8()).serialize([0, 1, 2]).toBytes());
// Example 2: On-chain derivation for `0xc0ffee + address('0x111')`
deriveObjectID('0xc0ffee', 'address', bcs.Address.serialize('0x111').toBytes());
// Example 3: On-chain derivation for `0xc0ffee + non-ascii string ("foo")`
deriveObjectID('0xc0ffee', '0x1::string::String', bcs.String.serialize('foo').toBytes());Deriving using custom types
To derive IDs using your custom objects, you can use BCS & the known type IDs.
Assuming a custom struct on-chain (for the key) being:
public struct DemoStruct has copy, store, drop { value: u64 }you can derive it by doing:
// Assuming we wanted to derive for key `DemoStruct { value: 1 }`.
const bcsType = bcs.struct('DemoStruct', {
value: bcs.u64(),
});
const key = bcsType.serialize({ value: 1 }).toBytes();
// Derive the object ID for the key `DemoStruct { value: 1 }`.
deriveObjectID('0xc0ffee', `0xc0ffee::demo::DemoStruct`, key);